[string.modifiers]

# 27 Strings library [[strings]](./#strings)

## 27.4 String classes [[string.classes]](string.classes#string.modifiers)

### 27.4.3 Class template basic_string [[basic.string]](basic.string#string.modifiers)

#### 27.4.3.7 Modifiers [string.modifiers]

#### [27.4.3.7.1](#string.op.append) basic_string​::​operator+= [[string.op.append]](string.op.append)

[🔗](#lib:operator+=,basic_string)

`constexpr basic_string& operator+=(const basic_string& str);
`

[1](#string.op.append-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3178)

*Effects*: Equivalent to: return append(str);

[🔗](#lib:operator+=,basic_string_)

`template<class T>
  constexpr basic_string& operator+=(const T& t);
`

[2](#string.op.append-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3192)

*Constraints*: 

- [(2.1)](#string.op.append-2.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(2.2)](#string.op.append-2.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.op.append-2.sentence-1)

[3](#string.op.append-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3203)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return append(sv);

[🔗](#lib:operator+=,basic_string__)

`constexpr basic_string& operator+=(const charT* s);
`

[4](#string.op.append-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3218)

*Effects*: Equivalent to: return append(s);

[🔗](#lib:operator+=,basic_string___)

`constexpr basic_string& operator+=(charT c);
`

[5](#string.op.append-5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3229)

*Effects*: Equivalent to: return append(size_type{1}, c);

[🔗](#lib:operator+=,basic_string____)

`constexpr basic_string& operator+=(initializer_list<charT> il);
`

[6](#string.op.append-6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3240)

*Effects*: Equivalent to: return append(il);

#### [27.4.3.7.2](#string.append) basic_string​::​append [[string.append]](string.append)

[🔗](#lib:append,basic_string)

`constexpr basic_string& append(const basic_string& str);
`

[1](#string.append-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3254)

*Effects*: Equivalent to: return append(str.data(), str.size());

[🔗](#lib:append,basic_string_)

`constexpr basic_string& append(const basic_string& str, size_type pos, size_type n = npos);
`

[2](#string.append-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3265)

*Effects*: Equivalent to:return append(basic_string_view<charT, traits>(str).substr(pos, n));

[🔗](#lib:append,basic_string__)

`template<class T>
  constexpr basic_string& append(const T& t);
`

[3](#string.append-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3280)

*Constraints*: 

- [(3.1)](#string.append-3.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(3.2)](#string.append-3.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.append-3.sentence-1)

[4](#string.append-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3291)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return append(sv.data(), sv.size());

[🔗](#lib:append,basic_string___)

`template<class T>
  constexpr basic_string& append(const T& t, size_type pos, size_type n = npos);
`

[5](#string.append-5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3307)

*Constraints*: 

- [(5.1)](#string.append-5.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(5.2)](#string.append-5.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.append-5.sentence-1)

[6](#string.append-6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3318)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return append(sv.substr(pos, n));

[🔗](#lib:append,basic_string____)

`constexpr basic_string& append(const charT* s, size_type n);
`

[7](#string.append-7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3333)

*Preconditions*: [s, s + n) is a valid range[.](#string.append-7.sentence-1)

[8](#string.append-8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3337)

*Effects*: Appends a copy of the range [s, s + n) to the string[.](#string.append-8.sentence-1)

[9](#string.append-9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3341)

*Returns*: *this[.](#string.append-9.sentence-1)

[🔗](#lib:append,basic_string_____)

`constexpr basic_string& append(const charT* s);
`

[10](#string.append-10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3352)

*Effects*: Equivalent to: return append(s, traits​::​length(s));

[🔗](#lib:append,basic_string______)

`constexpr basic_string& append(size_type n, charT c);
`

[11](#string.append-11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3363)

*Effects*: Appends n copies of c to the string[.](#string.append-11.sentence-1)

[12](#string.append-12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3367)

*Returns*: *this[.](#string.append-12.sentence-1)

[🔗](#lib:append,basic_string_______)

`template<class InputIterator>
  constexpr basic_string& append(InputIterator first, InputIterator last);
`

[13](#string.append-13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3379)

*Constraints*: InputIterator is a type that qualifies as an input
iterator ([[container.reqmts]](container.reqmts "23.2.2.2 Container requirements"))[.](#string.append-13.sentence-1)

[14](#string.append-14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3384)

*Effects*: Equivalent to: return append(basic_string(first, last, get_allocator()));

[🔗](#lib:append_range,basic_string)

`template<[container-compatible-range](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<charT> R>
  constexpr basic_string& append_range(R&& rg);
`

[15](#string.append-15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3396)

*Effects*: Equivalent to: return append(basic_string(from_range, std​::​forward<R>(rg), get_allocator()));

[🔗](#lib:append,basic_string________)

`constexpr basic_string& append(initializer_list<charT> il);
`

[16](#string.append-16)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3407)

*Effects*: Equivalent to: return append(il.begin(), il.size());

[🔗](#lib:push_back,basic_string)

`constexpr void push_back(charT c);
`

[17](#string.append-17)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3418)

*Effects*: Equivalent toappend(size_type{1}, c)[.](#string.append-17.sentence-1)

#### [27.4.3.7.3](#string.assign) basic_string​::​assign [[string.assign]](string.assign)

[🔗](#lib:assign,basic_string)

`constexpr basic_string& assign(const basic_string& str);
`

[1](#string.assign-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3432)

*Effects*: Equivalent to: return *this = str;

[🔗](#lib:assign,basic_string_)

`constexpr basic_string& assign(basic_string&& str)
  noexcept(allocator_traits<Allocator>::propagate_on_container_move_assignment::value ||
           allocator_traits<Allocator>::is_always_equal::value);
`

[2](#string.assign-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3445)

*Effects*: Equivalent to: return *this = std​::​move(str);

[🔗](#lib:assign,basic_string__)

`constexpr basic_string& assign(const basic_string& str, size_type pos, size_type n = npos);
`

[3](#string.assign-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3457)

*Effects*: Equivalent to:return assign(basic_string_view<charT, traits>(str).substr(pos, n));

[🔗](#lib:assign,basic_string___)

`template<class T>
  constexpr basic_string& assign(const T& t);
`

[4](#string.assign-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3472)

*Constraints*: 

- [(4.1)](#string.assign-4.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(4.2)](#string.assign-4.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.assign-4.sentence-1)

[5](#string.assign-5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3483)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return assign(sv.data(), sv.size());

[🔗](#lib:assign,basic_string____)

`template<class T>
  constexpr basic_string& assign(const T& t, size_type pos, size_type n = npos);
`

[6](#string.assign-6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3499)

*Constraints*: 

- [(6.1)](#string.assign-6.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(6.2)](#string.assign-6.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.assign-6.sentence-1)

[7](#string.assign-7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3510)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return assign(sv.substr(pos, n));

[🔗](#lib:assign,basic_string_____)

`constexpr basic_string& assign(const charT* s, size_type n);
`

[8](#string.assign-8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3525)

*Preconditions*: [s, s + n) is a valid range[.](#string.assign-8.sentence-1)

[9](#string.assign-9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3529)

*Effects*: Replaces the string controlled by *this with
a copy of the range [s, s + n)[.](#string.assign-9.sentence-1)

[10](#string.assign-10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3534)

*Returns*: *this[.](#string.assign-10.sentence-1)

[🔗](#lib:assign,basic_string______)

`constexpr basic_string& assign(const charT* s);
`

[11](#string.assign-11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3545)

*Effects*: Equivalent to: return assign(s, traits​::​length(s));

[🔗](#lib:assign,basic_string_______)

`constexpr basic_string& assign(initializer_list<charT> il);
`

[12](#string.assign-12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3556)

*Effects*: Equivalent to: return assign(il.begin(), il.size());

[🔗](#lib:assign,basic_string________)

`constexpr basic_string& assign(size_type n, charT c);
`

[13](#string.assign-13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3567)

*Effects*: Equivalent to:clear();
resize(n, c);return *this;

[🔗](#lib:assign,basic_string_________)

`template<class InputIterator>
  constexpr basic_string& assign(InputIterator first, InputIterator last);
`

[14](#string.assign-14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3584)

*Constraints*: InputIterator is a type that qualifies as an input
iterator ([[container.reqmts]](container.reqmts "23.2.2.2 Container requirements"))[.](#string.assign-14.sentence-1)

[15](#string.assign-15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3589)

*Effects*: Equivalent to: return assign(basic_string(first, last, get_allocator()));

[🔗](#lib:assign_range,basic_string)

`template<[container-compatible-range](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<charT> R>
  constexpr basic_string& assign_range(R&& rg);
`

[16](#string.assign-16)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3601)

*Effects*: Equivalent to: return assign(basic_string(from_range, std​::​forward<R>(rg), get_allocator()));

#### [27.4.3.7.4](#string.insert) basic_string​::​insert [[string.insert]](string.insert)

[🔗](#lib:insert,basic_string)

`constexpr basic_string& insert(size_type pos, const basic_string& str);
`

[1](#string.insert-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3614)

*Effects*: Equivalent to: return insert(pos, str.data(), str.size());

[🔗](#lib:insert,basic_string_)

`constexpr basic_string& insert(size_type pos1, const basic_string& str,
                               size_type pos2, size_type n = npos);
`

[2](#string.insert-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3626)

*Effects*: Equivalent to:return insert(pos1, basic_string_view<charT, traits>(str), pos2, n);

[🔗](#lib:insert,basic_string__)

`template<class T>
  constexpr basic_string& insert(size_type pos, const T& t);
`

[3](#string.insert-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3641)

*Constraints*: 

- [(3.1)](#string.insert-3.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(3.2)](#string.insert-3.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.insert-3.sentence-1)

[4](#string.insert-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3652)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return insert(pos, sv.data(), sv.size());

[🔗](#lib:insert,basic_string___)

`template<class T>
  constexpr basic_string& insert(size_type pos1, const T& t,
                                 size_type pos2, size_type n = npos);
`

[5](#string.insert-5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3669)

*Constraints*: 

- [(5.1)](#string.insert-5.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(5.2)](#string.insert-5.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.insert-5.sentence-1)

[6](#string.insert-6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3680)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return insert(pos1, sv.substr(pos2, n));

[🔗](#lib:insert,basic_string____)

`constexpr basic_string& insert(size_type pos, const charT* s, size_type n);
`

[7](#string.insert-7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3695)

*Preconditions*: [s, s + n) is a valid range[.](#string.insert-7.sentence-1)

[8](#string.insert-8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3699)

*Effects*: Inserts a copy of the range [s, s + n)
immediately before the character at position pos if pos < size(),
or otherwise at the end of the string[.](#string.insert-8.sentence-1)

[9](#string.insert-9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3705)

*Returns*: *this[.](#string.insert-9.sentence-1)

[10](#string.insert-10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3709)

*Throws*: 

- [(10.1)](#string.insert-10.1)

out_of_range if pos > size(),

- [(10.2)](#string.insert-10.2)

length_error if n > max_size() - size(), or

- [(10.3)](#string.insert-10.3)

any exceptions thrown by allocator_traits<Allocator>​::​allocate[.](#string.insert-10.sentence-1)

[🔗](#lib:insert,basic_string_____)

`constexpr basic_string& insert(size_type pos, const charT* s);
`

[11](#string.insert-11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3724)

*Effects*: Equivalent to: return insert(pos, s, traits​::​length(s));

[🔗](#lib:insert,basic_string______)

`constexpr basic_string& insert(size_type pos, size_type n, charT c);
`

[12](#string.insert-12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3735)

*Effects*: Inserts n copies of c before the character at position pos if pos < size(),
or otherwise at the end of the string[.](#string.insert-12.sentence-1)

[13](#string.insert-13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3741)

*Returns*: *this[.](#string.insert-13.sentence-1)

[14](#string.insert-14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3745)

*Throws*: 

- [(14.1)](#string.insert-14.1)

out_of_range if pos > size(),

- [(14.2)](#string.insert-14.2)

length_error if n > max_size() - size(), or

- [(14.3)](#string.insert-14.3)

any exceptions thrown by allocator_traits<Allocator>​::​allocate[.](#string.insert-14.sentence-1)

[🔗](#lib:insert,basic_string_______)

`constexpr iterator insert(const_iterator p, charT c);
`

[15](#string.insert-15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3760)

*Preconditions*: p is a valid iterator on*this[.](#string.insert-15.sentence-1)

[16](#string.insert-16)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3765)

*Effects*: Inserts a copy of c at the position p[.](#string.insert-16.sentence-1)

[17](#string.insert-17)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3769)

*Returns*: An iterator which refers to the inserted character[.](#string.insert-17.sentence-1)

[🔗](#lib:insert,basic_string________)

`constexpr iterator insert(const_iterator p, size_type n, charT c);
`

[18](#string.insert-18)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3780)

*Preconditions*: p is a valid iterator on*this[.](#string.insert-18.sentence-1)

[19](#string.insert-19)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3785)

*Effects*: Inserts n copies of c at the position p[.](#string.insert-19.sentence-1)

[20](#string.insert-20)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3789)

*Returns*: An iterator which refers to the first inserted character, orp if n == 0[.](#string.insert-20.sentence-1)

[🔗](#lib:insert,basic_string_________)

`template<class InputIterator>
  constexpr iterator insert(const_iterator p, InputIterator first, InputIterator last);
`

[21](#string.insert-21)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3802)

*Constraints*: InputIterator is a type that qualifies as an input
iterator ([[container.reqmts]](container.reqmts "23.2.2.2 Container requirements"))[.](#string.insert-21.sentence-1)

[22](#string.insert-22)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3807)

*Preconditions*: p is a valid iterator on*this[.](#string.insert-22.sentence-1)

[23](#string.insert-23)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3812)

*Effects*: Equivalent toinsert(p - begin(), basic_string(first, last, get_allocator()))[.](#string.insert-23.sentence-1)

[24](#string.insert-24)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3817)

*Returns*: An iterator which refers to the first inserted character, orp if first == last[.](#string.insert-24.sentence-1)

[🔗](#lib:insert_range,basic_string)

`template<[container-compatible-range](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<charT> R>
  constexpr iterator insert_range(const_iterator p, R&& rg);
`

[25](#string.insert-25)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3830)

*Preconditions*: p is a valid iterator on *this[.](#string.insert-25.sentence-1)

[26](#string.insert-26)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3834)

*Effects*: Equivalent toinsert(p - begin(), basic_string(from_range, std​::​forward<R>(rg), get_allocator()))[.](#string.insert-26.sentence-1)

[27](#string.insert-27)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3839)

*Returns*: An iterator which refers to the first inserted character, orp if rg is empty[.](#string.insert-27.sentence-1)

[🔗](#lib:insert,basic_string__________)

`constexpr iterator insert(const_iterator p, initializer_list<charT> il);
`

[28](#string.insert-28)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3851)

*Effects*: Equivalent to: return insert(p, il.begin(), il.end());

#### [27.4.3.7.5](#string.erase) basic_string​::​erase [[string.erase]](string.erase)

[🔗](#lib:erase,basic_string)

`constexpr basic_string& erase(size_type pos = 0, size_type n = npos);
`

[1](#string.erase-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3864)

*Effects*: Determines the effective length xlen of the string to be removed as the smaller of n andsize() - pos[.](#string.erase-1.sentence-1)

Removes the characters in the range [begin() + pos, begin() + pos + xlen)[.](#string.erase-1.sentence-2)

[2](#string.erase-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3871)

*Returns*: *this[.](#string.erase-2.sentence-1)

[3](#string.erase-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3875)

*Throws*: out_of_range if pos> size()[.](#string.erase-3.sentence-1)

[🔗](#lib:erase,basic_string_)

`constexpr iterator erase(const_iterator p);
`

[4](#string.erase-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3888)

*Preconditions*: p is a valid dereferenceable iterator on *this[.](#string.erase-4.sentence-1)

[5](#string.erase-5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3892)

*Effects*: Removes the character referred to by p[.](#string.erase-5.sentence-1)

[6](#string.erase-6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3896)

*Returns*: An iterator which points to the element immediately following p prior to
the element being erased[.](#string.erase-6.sentence-1)

If no such element exists,end() is returned[.](#string.erase-6.sentence-2)

[7](#string.erase-7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3904)

*Throws*: Nothing[.](#string.erase-7.sentence-1)

[🔗](#lib:erase,basic_string__)

`constexpr iterator erase(const_iterator first, const_iterator last);
`

[8](#string.erase-8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3915)

*Preconditions*: first and last are valid iterators on*this[.](#string.erase-8.sentence-1)

[first, last) is a valid range[.](#string.erase-8.sentence-2)

[9](#string.erase-9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3920)

*Effects*: Removes the characters in the range
[first, last)[.](#string.erase-9.sentence-1)

[10](#string.erase-10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3925)

*Returns*: An iterator which points to the element pointed to by last prior to
the other elements being erased[.](#string.erase-10.sentence-1)

If no such element exists,end() is returned[.](#string.erase-10.sentence-2)

[11](#string.erase-11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3933)

*Throws*: Nothing[.](#string.erase-11.sentence-1)

[🔗](#lib:pop_back,basic_string)

`constexpr void pop_back();
`

[12](#string.erase-12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3944)

*Hardened preconditions*: empty() is false[.](#string.erase-12.sentence-1)

[13](#string.erase-13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3948)

*Effects*: Equivalent to erase(end() - 1)[.](#string.erase-13.sentence-1)

[14](#string.erase-14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3952)

*Throws*: Nothing[.](#string.erase-14.sentence-1)

#### [27.4.3.7.6](#string.replace) basic_string​::​replace [[string.replace]](string.replace)

[🔗](#lib:replace,basic_string)

`constexpr basic_string& replace(size_type pos1, size_type n1, const basic_string& str);
`

[1](#string.replace-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3965)

*Effects*: Equivalent to: return replace(pos1, n1, str.data(), str.size());

[🔗](#lib:replace,basic_string_)

`constexpr basic_string& replace(size_type pos1, size_type n1, const basic_string& str,
                                size_type pos2, size_type n2 = npos);
`

[2](#string.replace-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3977)

*Effects*: Equivalent to:return replace(pos1, n1, basic_string_view<charT, traits>(str).substr(pos2, n2));

[🔗](#lib:replace,basic_string__)

`template<class T>
  constexpr basic_string& replace(size_type pos1, size_type n1, const T& t);
`

[3](#string.replace-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L3992)

*Constraints*: 

- [(3.1)](#string.replace-3.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(3.2)](#string.replace-3.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.replace-3.sentence-1)

[4](#string.replace-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4003)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return replace(pos1, n1, sv.data(), sv.size());

[🔗](#lib:replace,basic_string___)

`template<class T>
  constexpr basic_string& replace(size_type pos1, size_type n1, const T& t,
                                  size_type pos2, size_type n2 = npos);
`

[5](#string.replace-5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4020)

*Constraints*: 

- [(5.1)](#string.replace-5.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(5.2)](#string.replace-5.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.replace-5.sentence-1)

[6](#string.replace-6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4031)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return replace(pos1, n1, sv.substr(pos2, n2));

[🔗](#lib:replace,basic_string____)

`constexpr basic_string& replace(size_type pos1, size_type n1, const charT* s, size_type n2);
`

[7](#string.replace-7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4046)

*Preconditions*: [s, s + n2) is a valid range[.](#string.replace-7.sentence-1)

[8](#string.replace-8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4050)

*Effects*: Determines the effective length xlen of the string to be
removed as the smaller of n1 and size() - pos1[.](#string.replace-8.sentence-1)

Ifsize() - xlen >= max_size() - n2 throws length_error[.](#string.replace-8.sentence-2)

Otherwise,
the function replaces the characters in the range
[begin() + pos1, begin() + pos1 + xlen)
with a copy of the range [s, s + n2)[.](#string.replace-8.sentence-3)

[9](#string.replace-9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4059)

*Returns*: *this[.](#string.replace-9.sentence-1)

[10](#string.replace-10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4063)

*Throws*: 

- [(10.1)](#string.replace-10.1)

out_of_range if pos1 > size(),

- [(10.2)](#string.replace-10.2)

length_error if the length of the resulting string
would exceed max_size(), or

- [(10.3)](#string.replace-10.3)

any exceptions thrown by allocator_traits<Allocator>​::​allocate[.](#string.replace-10.sentence-1)

[🔗](#lib:replace,basic_string_____)

`constexpr basic_string& replace(size_type pos, size_type n, const charT* s);
`

[11](#string.replace-11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4079)

*Effects*: Equivalent to: return replace(pos, n, s, traits​::​length(s));

[🔗](#lib:replace,basic_string______)

`constexpr basic_string& replace(size_type pos1, size_type n1, size_type n2, charT c);
`

[12](#string.replace-12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4090)

*Effects*: Determines the effective length xlen of the string to be
removed as the smaller of n1 and size() - pos1[.](#string.replace-12.sentence-1)

Ifsize() - xlen >= max_size() - n2 throws length_error[.](#string.replace-12.sentence-2)

Otherwise,
the function replaces the characters in the range
[begin() + pos1, begin() + pos1 + xlen)
with n2 copies of c[.](#string.replace-12.sentence-3)

[13](#string.replace-13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4099)

*Returns*: *this[.](#string.replace-13.sentence-1)

[14](#string.replace-14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4103)

*Throws*: 

- [(14.1)](#string.replace-14.1)

out_of_range if pos1 > size(),

- [(14.2)](#string.replace-14.2)

length_error if the length of the resulting string
would exceed max_size(), or

- [(14.3)](#string.replace-14.3)

any exceptions thrown by allocator_traits<Allocator>​::​allocate.

[🔗](#lib:replace,basic_string_______)

`constexpr basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);
`

[15](#string.replace-15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4119)

*Effects*: Equivalent to: return replace(i1, i2, basic_string_view<charT, traits>(str));

[🔗](#lib:replace,basic_string________)

`template<class T>
  constexpr basic_string& replace(const_iterator i1, const_iterator i2, const T& t);
`

[16](#string.replace-16)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4131)

*Constraints*: 

- [(16.1)](#string.replace-16.1)

is_convertible_v<const T&, basic_string_view<charT, traits>> istrue and

- [(16.2)](#string.replace-16.2)

is_convertible_v<const T&, const charT*> isfalse[.](#string.replace-16.sentence-1)

[17](#string.replace-17)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4142)

*Preconditions*: [begin(), i1) and [i1, i2) are valid ranges[.](#string.replace-17.sentence-1)

[18](#string.replace-18)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4146)

*Effects*: Equivalent to:basic_string_view<charT, traits> sv = t;return replace(i1 - begin(), i2 - i1, sv.data(), sv.size());

[🔗](#lib:replace,basic_string_________)

`constexpr basic_string& replace(const_iterator i1, const_iterator i2, const charT* s, size_type n);
`

[19](#string.replace-19)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4161)

*Effects*: Equivalent to: return replace(i1, i2, basic_string_view<charT, traits>(s, n));

[🔗](#lib:replace,basic_string__________)

`constexpr basic_string& replace(const_iterator i1, const_iterator i2, const charT* s);
`

[20](#string.replace-20)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4172)

*Effects*: Equivalent to: return replace(i1, i2, basic_string_view<charT, traits>(s));

[🔗](#lib:replace,basic_string___________)

`constexpr basic_string& replace(const_iterator i1, const_iterator i2, size_type n, charT c);
`

[21](#string.replace-21)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4183)

*Preconditions*: [begin(), i1) and [i1, i2) are valid ranges[.](#string.replace-21.sentence-1)

[22](#string.replace-22)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4187)

*Effects*: Equivalent to: return replace(i1 - begin(), i2 - i1, n, c);

[🔗](#lib:replace,basic_string____________)

`template<class InputIterator>
  constexpr basic_string& replace(const_iterator i1, const_iterator i2,
                                  InputIterator j1, InputIterator j2);
`

[23](#string.replace-23)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4200)

*Constraints*: InputIterator is a type that qualifies as an input
iterator ([[container.reqmts]](container.reqmts "23.2.2.2 Container requirements"))[.](#string.replace-23.sentence-1)

[24](#string.replace-24)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4205)

*Effects*: Equivalent to: return replace(i1, i2, basic_string(j1, j2, get_allocator()));

[🔗](#lib:replace_with_range,basic_string)

`template<[container-compatible-range](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<charT> R>
  constexpr basic_string& replace_with_range(const_iterator i1, const_iterator i2, R&& rg);
`

[25](#string.replace-25)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4217)

*Effects*: Equivalent to:return replace(i1, i2, basic_string(from_range, std::forward<R>(rg), get_allocator()));

[🔗](#lib:replace,basic_string_____________)

`constexpr basic_string& replace(const_iterator i1, const_iterator i2, initializer_list<charT> il);
`

[26](#string.replace-26)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4231)

*Effects*: Equivalent to: return replace(i1, i2, il.begin(), il.size());

#### [27.4.3.7.7](#string.copy) basic_string​::​copy [[string.copy]](string.copy)

[🔗](#lib:copy,basic_string)

`constexpr size_type copy(charT* s, size_type n, size_type pos = 0) const;
`

[1](#string.copy-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4244)

*Effects*: Equivalent to:return basic_string_view<charT, traits>(*this).copy(s, n, pos);

[*Note [1](#string.copy-note-1)*:

This does not terminate s with a null object[.](#string.copy-1.sentence-1)

— *end note*]

#### [27.4.3.7.8](#string.swap) basic_string​::​swap [[string.swap]](string.swap)

[🔗](#lib:swap,basic_string)

`constexpr void swap(basic_string& s)
  noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value ||
           allocator_traits<Allocator>::is_always_equal::value);
`

[1](#string.swap-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4263)

*Preconditions*: allocator_traits<Allocator>​::​propagate_on_container_swap​::​value is true orget_allocator() == s.get_allocator()[.](#string.swap-1.sentence-1)

[2](#string.swap-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4269)

*Postconditions*: *this contains the same sequence of characters that was in s,s contains the same sequence of characters that was in*this[.](#string.swap-2.sentence-1)

[3](#string.swap-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4276)

*Throws*: Nothing[.](#string.swap-3.sentence-1)

[4](#string.swap-4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L4280)

*Complexity*: Constant time[.](#string.swap-4.sentence-1)