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struct

String

Represents a mutable string.

Implemented traits​

AnyType, Boolable, CollectionElement, Copyable, EqualityComparable, Formattable, Hashable, IntableRaising, KeyElement, Movable, Sized, Stringable, ToFormatter

Methods​

__init__​

__init__(inout self: Self, /, owned impl: List[SIMD[int8, 1]])

Construct a string from a buffer of bytes.

The buffer must be terminated with a null byte:

var buf = List[Int8]()
buf.append(ord('H'))
buf.append(ord('i'))
buf.append(0)
var hi = String(buf)

Args:

  • ​impl (List[SIMD[int8, 1]]): The buffer.

__init__(inout self: Self, /)

Construct an uninitialized string.

__init__(inout self: Self, /, str: StringRef)

Construct a string from a StringRef object.

Args:

  • ​str (StringRef): The StringRef from which to construct this string object.

__init__(inout self: Self, /, str: StringLiteral)

Constructs a String value given a constant string.

Args:

  • ​str (StringLiteral): The input constant string.

__init__[stringable: Stringable](inout self: Self, /, value: stringable)

Creates a string from a value that conforms to Stringable trait.

Parameters:

  • ​stringable (Stringable): The Stringable type.

Args:

  • ​value (stringable): The value that conforms to Stringable.

__init__(inout self: Self, /, ptr: UnsafePointer[SIMD[int8, 1], 0], len: Int)

Creates a string from the buffer. Note that the string now owns the buffer.

The buffer must be terminated with a null byte.

Args:

  • ​ptr (UnsafePointer[SIMD[int8, 1], 0]): The pointer to the buffer.
  • ​len (Int): The length of the buffer, including the null terminator.

__init__(inout self: Self, /, ptr: LegacyPointer[SIMD[int8, 1], 0], len: Int)

Creates a string from the buffer. Note that the string now owns the buffer.

The buffer must be terminated with a null byte.

Args:

  • ​ptr (LegacyPointer[SIMD[int8, 1], 0]): The pointer to the buffer.
  • ​len (Int): The length of the buffer, including the null terminator.

__init__(inout self: Self, /, ptr: DTypePointer[int8, 0], len: Int)

Creates a string from the buffer. Note that the string now owns the buffer.

The buffer must be terminated with a null byte.

Args:

  • ​ptr (DTypePointer[int8, 0]): The pointer to the buffer.
  • ​len (Int): The length of the buffer, including the null terminator.

__copyinit__​

__copyinit__(inout self: Self, /, existing: Self)

Creates a deep copy of an existing string.

Args:

  • ​existing (Self): The string to copy.

__moveinit__​

__moveinit__(inout self: Self, /, owned existing: Self)

Move the value of a string.

Args:

  • ​existing (Self): The string to move.

__bool__​

__bool__(self: Self) -> Bool

Checks if the string is not empty.

Returns:

True if the string length is greater than zero, and False otherwise.

__getitem__​

__getitem__(self: Self, idx: Int) -> Self

Gets the character at the specified position.

Args:

  • ​idx (Int): The index value.

Returns:

A new string containing the character at the specified position.

__getitem__(self: Self, span: Slice) -> Self

Gets the sequence of characters at the specified positions.

Args:

  • ​span (Slice): A slice that specifies positions of the new substring.

Returns:

A new string containing the string at the specified positions.

__eq__​

__eq__(self: Self, other: Self) -> Bool

Compares two Strings if they have the same values.

Args:

  • ​other (Self): The rhs of the operation.

Returns:

True if the Strings are equal and False otherwise.

__ne__​

__ne__(self: Self, other: Self) -> Bool

Compares two Strings if they do not have the same values.

Args:

  • ​other (Self): The rhs of the operation.

Returns:

True if the Strings are not equal and False otherwise.

__contains__​

__contains__(self: Self, substr: Self) -> Bool

Returns True if the substring is contained within the current string.

Args:

  • ​substr (Self): The substring to check.

Returns:

True if the string contains the substring.

__add__​

__add__(self: Self, other: Self) -> Self

Creates a string by appending another string at the end.

Args:

  • ​other (Self): The string to append.

Returns:

The new constructed string.

__mul__​

__mul__(self: Self, n: Int) -> Self

Concatenates the string n times.

Args:

  • ​n (Int): The number of times to concatenate the string.

Returns:

The string concantenated n times.

__radd__​

__radd__(self: Self, other: Self) -> Self

Creates a string by prepending another string to the start.

Args:

  • ​other (Self): The string to prepend.

Returns:

The new constructed string.

__iadd__​

__iadd__(inout self: Self, other: Self)

Appends another string to this string.

Args:

  • ​other (Self): The string to append.

__str__​

__str__(self: Self) -> Self

__len__​

__len__(self: Self) -> Int

Returns the string length.

Returns:

The string length.

format_sequence​

static format_sequence[*Ts: Formattable](*args: *Ts) -> Self

Construct a string by concatenating a sequence of formattable arguments.

Parameters:

  • ​*Ts (Formattable): The types of the arguments to format. Each type must be satisfy Formattable.

Args:

  • ​*args (*Ts): A sequence of formattable arguments.

Returns:

A string formed by formatting the argument sequence.

format_to​

format_to(self: Self, inout writer: Formatter)

Formats this string to the provided formatter.

Args:

  • ​writer (Formatter): The formatter to write to.

join​

join[rank: Int](self: Self, elems: StaticIntTuple[rank]) -> Self

Joins the elements from the tuple using the current string as a delimiter.

Parameters:

  • ​rank (Int): The size of the tuple.

Args:

  • ​elems (StaticIntTuple[rank]): The input tuple.

Returns:

The joined string.

join[*Types: Stringable](self: Self, *elems: *Types) -> Self

Joins string elements using the current string as a delimiter.

Parameters:

  • ​*Types (Stringable): The types of the elements.

Args:

  • ​*elems (*Types): The input values.

Returns:

The joined string.

as_bytes​

as_bytes(self: Self) -> List[SIMD[int8, 1]]

Retrieves the underlying byte sequence encoding the characters in this string.

This does not include the trailing null terminator.

Returns:

A sequence containing the encoded characters stored in this string.

count​

count(self: Self, substr: Self) -> Int

Return the number of non-overlapping occurrences of substring substr in the string.

If sub is empty, returns the number of empty strings between characters which is the length of the string plus one.

Args:

  • ​substr (Self): The substring to count.

Returns:

The number of occurrences of substr.

find​

find(self: Self, substr: Self, start: Int = 0) -> Int

Finds the offset of the first occurrence of substr starting at start. If not found, returns -1.

Args:

  • ​substr (Self): The substring to find.
  • ​start (Int): The offset from which to find.

Returns:

The offset of substr relative to the beginning of the string.

rfind​

rfind(self: Self, substr: Self, start: Int = 0) -> Int

Finds the offset of the last occurrence of substr starting at start. If not found, returns -1.

Args:

  • ​substr (Self): The substring to find.
  • ​start (Int): The offset from which to find.

Returns:

The offset of substr relative to the beginning of the string.

split​

split(self: Self, delimiter: Self) -> List[String]

Split the string by a delimiter.

Args:

  • ​delimiter (Self): The string to split on.

Returns:

A List of Strings containing the input split by the delimiter.

Raises:

Error if an empty delimiter is specified.

replace​

replace(self: Self, old: Self, new: Self) -> Self

Return a copy of the string with all occurrences of substring old if replaced by new.

Args:

  • ​old (Self): The substring to replace.
  • ​new (Self): The substring to replace with.

Returns:

The string where all occurences of old are replaced with new.

strip​

strip(self: Self) -> Self

Return a copy of the string with leading and trailing whitespace characters removed.

See isspace for a list of whitespace characters

Returns:

A copy of the string with no leading or trailing whitespace characters.

rstrip​

rstrip(self: Self) -> Self

Return a copy of the string with trailing whitespace characters removed.

See isspace for a list of whitespace characters

Returns:

A copy of the string with no trailing whitespace characters.

lstrip​

lstrip(self: Self) -> Self

Return a copy of the string with leading whitespace characters removed.

See isspace for a list of whitespace characters

Returns:

A copy of the string with no leading whitespace characters.

__hash__​

__hash__(self: Self) -> Int

Hash the underlying buffer using builtin hash.

Returns:

A 64-bit hash value. This value is not suitable for cryptographic uses. Its intended usage is for data structures. See the hash builtin documentation for more details.

lower​

lower(self: Self) -> Self

Returns a copy of the string with all ASCII cased characters converted to lowercase.

Returns:

A new string where cased letters have been convered to lowercase.

upper​

upper(self: Self) -> Self

Returns a copy of the string with all ASCII cased characters converted to uppercase.

Returns:

A new string where cased letters have been converted to uppercase.

startswith​

startswith(self: Self, prefix: Self, start: Int = 0, end: Int = -1) -> Bool

Checks if the string starts with the specified prefix between start and end positions. Returns True if found and False otherwise.

Args:

  • ​prefix (Self): The prefix to check.
  • ​start (Int): The start offset from which to check.
  • ​end (Int): The end offset from which to check.

Returns:

True if the self[start:end] is prefixed by the input prefix.

endswith​

endswith(self: Self, suffix: Self, start: Int = 0, end: Int = -1) -> Bool

Checks if the string end with the specified suffix between start and end positions. Returns True if found and False otherwise.

Args:

  • ​suffix (Self): The suffix to check.
  • ​start (Int): The start offset from which to check.
  • ​end (Int): The end offset from which to check.

Returns:

True if the self[start:end] is suffixed by the input suffix.

removeprefix​

removeprefix(self: Self, prefix: Self, /) -> Self

If the string starts with the prefix string, return string[len(prefix):]. Otherwise, return a copy of the original string.

print(String('TestHook').removeprefix('Test'))
# 'Hook'
print(String('BaseTestCase').removeprefix('Test'))
# 'BaseTestCase'

Args:

  • ​prefix (Self): The prefix to remove from the string.

Returns:

A new string with the prefix removed if it was present.

removesuffix​

removesuffix(self: Self, suffix: Self, /) -> Self

If the string ends with the suffix string, return string[:-len(suffix)]. Otherwise, return a copy of the original string.

print(String('TestHook').removesuffix('Hook'))
# 'Test'
print(String('BaseTestCase').removesuffix('Test'))
# 'BaseTestCase'

Args:

  • ​suffix (Self): The suffix to remove from the string.

Returns:

A new string with the suffix removed if it was present.

__int__​

__int__(self: Self) -> Int

Parses the given string as a base-10 integer and returns that value.

For example, int("19") returns 19. If the given string cannot be parsed as an integer value, an error is raised. For example, int("hi") raises an error.

Returns:

An integer value that represents the string, or otherwise raises.