char - Rust
source link: https://doc.rust-lang.org/stable/std/primitive.char.html
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Implementations
The highest valid code point a char
can have.
A char
is a Unicode Scalar Value, which means that it is a Code
Point, but only ones within a certain range. MAX
is the highest valid
code point that’s a valid Unicode Scalar Value.
U+FFFD REPLACEMENT CHARACTER
(�) is used in Unicode to represent a
decoding error.
It can occur, for example, when giving ill-formed UTF-8 bytes to
String::from_utf8_lossy
.
The version of Unicode that the Unicode parts of
char
and str
methods are based on.
New versions of Unicode are released regularly and subsequently all methods
in the standard library depending on Unicode are updated. Therefore the
behavior of some char
and str
methods and the value of this constant
changes over time. This is not considered to be a breaking change.
The version numbering scheme is explained in Unicode 11.0 or later, Section 3.1 Versions of the Unicode Standard.
Creates an iterator over the UTF-16 encoded code points in iter
,
returning unpaired surrogates as Err
s.
Examples
Basic usage:
use std::char::decode_utf16;
// 𝄞mus<invalid>ic<invalid>
let v = [
0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0xDD1E, 0x0069, 0x0063, 0xD834,
];
assert_eq!(
decode_utf16(v)
.map(|r| r.map_err(|e| e.unpaired_surrogate()))
.collect::<Vec<_>>(),
vec![
Ok('𝄞'),
Ok('m'), Ok('u'), Ok('s'),
Err(0xDD1E),
Ok('i'), Ok('c'),
Err(0xD834)
]
);
RunA lossy decoder can be obtained by replacing Err
results with the replacement character:
use std::char::{decode_utf16, REPLACEMENT_CHARACTER};
// 𝄞mus<invalid>ic<invalid>
let v = [
0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0xDD1E, 0x0069, 0x0063, 0xD834,
];
assert_eq!(
decode_utf16(v)
.map(|r| r.unwrap_or(REPLACEMENT_CHARACTER))
.collect::<String>(),
"𝄞mus�ic�"
);
RunConverts a u32
to a char
.
Note that all char
s are valid u32
s, and can be cast to one with
as
:
let c = '💯';
let i = c as u32;
assert_eq!(128175, i);
RunHowever, the reverse is not true: not all valid u32
s are valid
char
s. from_u32()
will return None
if the input is not a valid value
for a char
.
For an unsafe version of this function which ignores these checks, see
from_u32_unchecked
.
Examples
Basic usage:
use std::char;
let c = char::from_u32(0x2764);
assert_eq!(Some('❤'), c);
RunReturning None
when the input is not a valid char
:
use std::char;
let c = char::from_u32(0x110000);
assert_eq!(None, c);
RunConverts a u32
to a char
, ignoring validity.
Note that all char
s are valid u32
s, and can be cast to one with
as
:
let c = '💯';
let i = c as u32;
assert_eq!(128175, i);
RunHowever, the reverse is not true: not all valid u32
s are valid
char
s. from_u32_unchecked()
will ignore this, and blindly cast to
char
, possibly creating an invalid one.
Safety
This function is unsafe, as it may construct invalid char
values.
For a safe version of this function, see the from_u32
function.
Examples
Basic usage:
use std::char;
let c = unsafe { char::from_u32_unchecked(0x2764) };
assert_eq!('❤', c);
RunConverts a digit in the given radix to a char
.
A ‘radix’ here is sometimes also called a ‘base’. A radix of two indicates a binary number, a radix of ten, decimal, and a radix of sixteen, hexadecimal, to give some common values. Arbitrary radices are supported.
from_digit()
will return None
if the input is not a digit in
the given radix.
Panics
Panics if given a radix larger than 36.
Examples
Basic usage:
use std::char;
let c = char::from_digit(4, 10);
assert_eq!(Some('4'), c);
// Decimal 11 is a single digit in base 16
let c = char::from_digit(11, 16);
assert_eq!(Some('b'), c);
RunReturning None
when the input is not a digit:
use std::char;
let c = char::from_digit(20, 10);
assert_eq!(None, c);
RunPassing a large radix, causing a panic:
use std::char;
// this panics
let _c = char::from_digit(1, 37);
RunChecks if a char
is a digit in the given radix.
A ‘radix’ here is sometimes also called a ‘base’. A radix of two indicates a binary number, a radix of ten, decimal, and a radix of sixteen, hexadecimal, to give some common values. Arbitrary radices are supported.
Compared to is_numeric()
, this function only recognizes the characters
0-9
, a-z
and A-Z
.
‘Digit’ is defined to be only the following characters:
0-9
a-z
A-Z
For a more comprehensive understanding of ‘digit’, see is_numeric()
.
Panics
Panics if given a radix larger than 36.
Examples
Basic usage:
assert!('1'.is_digit(10));
assert!('f'.is_digit(16));
assert!(!'f'.is_digit(10));
RunPassing a large radix, causing a panic:
// this panics
'1'.is_digit(37);
RunConverts a char
to a digit in the given radix.
A ‘radix’ here is sometimes also called a ‘base’. A radix of two indicates a binary number, a radix of ten, decimal, and a radix of sixteen, hexadecimal, to give some common values. Arbitrary radices are supported.
‘Digit’ is defined to be only the following characters:
0-9
a-z
A-Z
Errors
Returns None
if the char
does not refer to a digit in the given radix.
Panics
Panics if given a radix larger than 36.
Examples
Basic usage:
assert_eq!('1'.to_digit(10), Some(1));
assert_eq!('f'.to_digit(16), Some(15));
RunPassing a non-digit results in failure:
assert_eq!('f'.to_digit(10), None);
assert_eq!('z'.to_digit(16), None);
RunPassing a large radix, causing a panic:
// this panics
let _ = '1'.to_digit(37);
RunReturns an iterator that yields the hexadecimal Unicode escape of a
character as char
s.
This will escape characters with the Rust syntax of the form
\u{NNNNNN}
where NNNNNN
is a hexadecimal representation.
Examples
As an iterator:
for c in '❤'.escape_unicode() {
print!("{}", c);
}
println!();
RunUsing println!
directly:
println!("{}", '❤'.escape_unicode());
RunBoth are equivalent to:
println!("\\u{{2764}}");
RunUsing to_string
:
assert_eq!('❤'.escape_unicode().to_string(), "\\u{2764}");
RunReturns an iterator that yields the literal escape code of a character
as char
s.
This will escape the characters similar to the Debug
implementations
of str
or char
.
Examples
As an iterator:
for c in '\n'.escape_debug() {
print!("{}", c);
}
println!();
RunUsing println!
directly:
println!("{}", '\n'.escape_debug());
RunBoth are equivalent to:
println!("\\n");
RunUsing to_string
:
assert_eq!('\n'.escape_debug().to_string(), "\\n");
RunReturns an iterator that yields the literal escape code of a character
as char
s.
The default is chosen with a bias toward producing literals that are legal in a variety of languages, including C++11 and similar C-family languages. The exact rules are:
- Tab is escaped as
\t
. - Carriage return is escaped as
\r
. - Line feed is escaped as
\n
. - Single quote is escaped as
\'
. - Double quote is escaped as
\"
. - Backslash is escaped as
\\
. - Any character in the ‘printable ASCII’ range
0x20
..0x7e
inclusive is not escaped. - All other characters are given hexadecimal Unicode escapes; see
escape_unicode
.
Examples
As an iterator:
for c in '"'.escape_default() {
print!("{}", c);
}
println!();
RunUsing println!
directly:
println!("{}", '"'.escape_default());
RunBoth are equivalent to:
println!("\\\"");
RunUsing to_string
:
assert_eq!('"'.escape_default().to_string(), "\\\"");
RunReturns the number of bytes this char
would need if encoded in UTF-8.
That number of bytes is always between 1 and 4, inclusive.
Examples
Basic usage:
let len = 'A'.len_utf8();
assert_eq!(len, 1);
let len = 'ß'.len_utf8();
assert_eq!(len, 2);
let len = 'ℝ'.len_utf8();
assert_eq!(len, 3);
let len = '💣'.len_utf8();
assert_eq!(len, 4);
RunThe &str
type guarantees that its contents are UTF-8, and so we can compare the length it
would take if each code point was represented as a char
vs in the &str
itself:
// as chars
let eastern = '東';
let capital = '京';
// both can be represented as three bytes
assert_eq!(3, eastern.len_utf8());
assert_eq!(3, capital.len_utf8());
// as a &str, these two are encoded in UTF-8
let tokyo = "東京";
let len = eastern.len_utf8() + capital.len_utf8();
// we can see that they take six bytes total...
assert_eq!(6, tokyo.len());
// ... just like the &str
assert_eq!(len, tokyo.len());
RunReturns the number of 16-bit code units this char
would need if
encoded in UTF-16.
See the documentation for len_utf8()
for more explanation of this
concept. This function is a mirror, but for UTF-16 instead of UTF-8.
Examples
Basic usage:
let n = 'ß'.len_utf16();
assert_eq!(n, 1);
let len = '💣'.len_utf16();
assert_eq!(len, 2);
Runpub fn encode_utf8(self, dst: &mut [u8]) -> &mut str
Encodes this character as UTF-8 into the provided byte buffer, and then returns the subslice of the buffer that contains the encoded character.
Panics
Panics if the buffer is not large enough.
A buffer of length four is large enough to encode any char
.
Examples
In both of these examples, ‘ß’ takes two bytes to encode.
let mut b = [0; 2];
let result = 'ß'.encode_utf8(&mut b);
assert_eq!(result, "ß");
assert_eq!(result.len(), 2);
RunA buffer that’s too small:
let mut b = [0; 1];
// this panics
'ß'.encode_utf8(&mut b);
RunEncodes this character as UTF-16 into the provided u16
buffer,
and then returns the subslice of the buffer that contains the encoded character.
Panics
Panics if the buffer is not large enough.
A buffer of length 2 is large enough to encode any char
.
Examples
In both of these examples, ‘𝕊’ takes two u16
s to encode.
let mut b = [0; 2];
let result = '𝕊'.encode_utf16(&mut b);
assert_eq!(result.len(), 2);
RunA buffer that’s too small:
let mut b = [0; 1];
// this panics
'𝕊'.encode_utf16(&mut b);
RunReturns true
if this char
has the Alphabetic
property.
Alphabetic
is described in Chapter 4 (Character Properties) of the Unicode Standard and
specified in the Unicode Character Database DerivedCoreProperties.txt
.
Examples
Basic usage:
assert!('a'.is_alphabetic());
assert!('京'.is_alphabetic());
let c = '💝';
// love is many things, but it is not alphabetic
assert!(!c.is_alphabetic());
RunReturns true
if this char
has the Lowercase
property.
Lowercase
is described in Chapter 4 (Character Properties) of the Unicode Standard and
specified in the Unicode Character Database DerivedCoreProperties.txt
.
Examples
Basic usage:
assert!('a'.is_lowercase());
assert!('δ'.is_lowercase());
assert!(!'A'.is_lowercase());
assert!(!'Δ'.is_lowercase());
// The various Chinese scripts and punctuation do not have case, and so:
assert!(!'中'.is_lowercase());
assert!(!' '.is_lowercase());
RunReturns true
if this char
has the Uppercase
property.
Uppercase
is described in Chapter 4 (Character Properties) of the Unicode Standard and
specified in the Unicode Character Database DerivedCoreProperties.txt
.
Examples
Basic usage:
assert!(!'a'.is_uppercase());
assert!(!'δ'.is_uppercase());
assert!('A'.is_uppercase());
assert!('Δ'.is_uppercase());
// The various Chinese scripts and punctuation do not have case, and so:
assert!(!'中'.is_uppercase());
assert!(!' '.is_uppercase());
RunReturns true
if this char
has the White_Space
property.
White_Space
is specified in the Unicode Character Database PropList.txt
.
Examples
Basic usage:
assert!(' '.is_whitespace());
// a non-breaking space
assert!('\u{A0}'.is_whitespace());
assert!(!'越'.is_whitespace());
RunReturns true
if this char
satisfies either is_alphabetic()
or is_numeric()
.
Examples
Basic usage:
assert!('٣'.is_alphanumeric());
assert!('7'.is_alphanumeric());
assert!('৬'.is_alphanumeric());
assert!('¾'.is_alphanumeric());
assert!('①'.is_alphanumeric());
assert!('K'.is_alphanumeric());
assert!('و'.is_alphanumeric());
assert!('藏'.is_alphanumeric());
RunReturns true
if this char
has the general category for control codes.
Control codes (code points with the general category of Cc
) are described in Chapter 4
(Character Properties) of the Unicode Standard and specified in the Unicode Character
Database UnicodeData.txt
.
Examples
Basic usage:
// U+009C, STRING TERMINATOR
assert!(''.is_control());
assert!(!'q'.is_control());
RunReturns true
if this char
has one of the general categories for numbers.
The general categories for numbers (Nd
for decimal digits, Nl
for letter-like numeric
characters, and No
for other numeric characters) are specified in the Unicode Character
Database UnicodeData.txt
.
Examples
Basic usage:
assert!('٣'.is_numeric());
assert!('7'.is_numeric());
assert!('৬'.is_numeric());
assert!('¾'.is_numeric());
assert!('①'.is_numeric());
assert!(!'K'.is_numeric());
assert!(!'و'.is_numeric());
assert!(!'藏'.is_numeric());
RunReturns an iterator that yields the lowercase mapping of this char
as one or more
char
s.
If this char
does not have a lowercase mapping, the iterator yields the same char
.
If this char
has a one-to-one lowercase mapping given by the Unicode Character
Database UnicodeData.txt
, the iterator yields that char
.
If this char
requires special considerations (e.g. multiple char
s) the iterator yields
the char
(s) given by SpecialCasing.txt
.
This operation performs an unconditional mapping without tailoring. That is, the conversion is independent of context and language.
In the Unicode Standard, Chapter 4 (Character Properties) discusses case mapping in general and Chapter 3 (Conformance) discusses the default algorithm for case conversion.
Examples
As an iterator:
for c in 'İ'.to_lowercase() {
print!("{}", c);
}
println!();
RunUsing println!
directly:
println!("{}", 'İ'.to_lowercase());
RunBoth are equivalent to:
println!("i\u{307}");
RunUsing to_string
:
assert_eq!('C'.to_lowercase().to_string(), "c");
// Sometimes the result is more than one character:
assert_eq!('İ'.to_lowercase().to_string(), "i\u{307}");
// Characters that do not have both uppercase and lowercase
// convert into themselves.
assert_eq!('山'.to_lowercase().to_string(), "山");
RunReturns an iterator that yields the uppercase mapping of this char
as one or more
char
s.
If this char
does not have an uppercase mapping, the iterator yields the same char
.
If this char
has a one-to-one uppercase mapping given by the Unicode Character
Database UnicodeData.txt
, the iterator yields that char
.
If this char
requires special considerations (e.g. multiple char
s) the iterator yields
the char
(s) given by SpecialCasing.txt
.
This operation performs an unconditional mapping without tailoring. That is, the conversion is independent of context and language.
In the Unicode Standard, Chapter 4 (Character Properties) discusses case mapping in general and Chapter 3 (Conformance) discusses the default algorithm for case conversion.
Examples
As an iterator:
for c in 'ß'.to_uppercase() {
print!("{}", c);
}
println!();
RunUsing println!
directly:
println!("{}", 'ß'.to_uppercase());
RunBoth are equivalent to:
println!("SS");
RunUsing to_string
:
assert_eq!('c'.to_uppercase().to_string(), "C");
// Sometimes the result is more than one character:
assert_eq!('ß'.to_uppercase().to_string(), "SS");
// Characters that do not have both uppercase and lowercase
// convert into themselves.
assert_eq!('山'.to_uppercase().to_string(), "山");
RunNote on locale
In Turkish, the equivalent of ‘i’ in Latin has five forms instead of two:
- ‘Dotless’: I / ı, sometimes written ï
- ‘Dotted’: İ / i
Note that the lowercase dotted ‘i’ is the same as the Latin. Therefore:
let upper_i = 'i'.to_uppercase().to_string();
RunThe value of upper_i
here relies on the language of the text: if we’re
in en-US
, it should be "I"
, but if we’re in tr_TR
, it should
be "İ"
. to_uppercase()
does not take this into account, and so:
let upper_i = 'i'.to_uppercase().to_string();
assert_eq!(upper_i, "I");
Runholds across languages.
Checks if the value is within the ASCII range.
Examples
let ascii = 'a';
let non_ascii = '❤';
assert!(ascii.is_ascii());
assert!(!non_ascii.is_ascii());
Runpub const fn to_ascii_uppercase(&self) -> char
Makes a copy of the value in its ASCII upper case equivalent.
ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.
To uppercase the value in-place, use make_ascii_uppercase()
.
To uppercase ASCII characters in addition to non-ASCII characters, use
to_uppercase()
.
Examples
let ascii = 'a';
let non_ascii = '❤';
assert_eq!('A', ascii.to_ascii_uppercase());
assert_eq!('❤', non_ascii.to_ascii_uppercase());
Runpub const fn to_ascii_lowercase(&self) -> char
Makes a copy of the value in its ASCII lower case equivalent.
ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.
To lowercase the value in-place, use make_ascii_lowercase()
.
To lowercase ASCII characters in addition to non-ASCII characters, use
to_lowercase()
.
Examples
let ascii = 'A';
let non_ascii = '❤';
assert_eq!('a', ascii.to_ascii_lowercase());
assert_eq!('❤', non_ascii.to_ascii_lowercase());
Runpub const fn eq_ignore_ascii_case(&self, other: &char) -> bool
Checks that two values are an ASCII case-insensitive match.
Equivalent to to_ascii_lowercase(a) == to_ascii_lowercase(b)
.
Examples
let upper_a = 'A';
let lower_a = 'a';
let lower_z = 'z';
assert!(upper_a.eq_ignore_ascii_case(&lower_a));
assert!(upper_a.eq_ignore_ascii_case(&upper_a));
assert!(!upper_a.eq_ignore_ascii_case(&lower_z));
RunConverts this type to its ASCII upper case equivalent in-place.
ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.
To return a new uppercased value without modifying the existing one, use
to_ascii_uppercase()
.
Examples
let mut ascii = 'a';
ascii.make_ascii_uppercase();
assert_eq!('A', ascii);
RunConverts this type to its ASCII lower case equivalent in-place.
ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.
To return a new lowercased value without modifying the existing one, use
to_ascii_lowercase()
.
Examples
let mut ascii = 'A';
ascii.make_ascii_lowercase();
assert_eq!('a', ascii);
Runpub const fn is_ascii_alphabetic(&self) -> bool
Checks if the value is an ASCII alphabetic character:
- U+0041 ‘A’ ..= U+005A ‘Z’, or
- U+0061 ‘a’ ..= U+007A ‘z’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(uppercase_a.is_ascii_alphabetic());
assert!(uppercase_g.is_ascii_alphabetic());
assert!(a.is_ascii_alphabetic());
assert!(g.is_ascii_alphabetic());
assert!(!zero.is_ascii_alphabetic());
assert!(!percent.is_ascii_alphabetic());
assert!(!space.is_ascii_alphabetic());
assert!(!lf.is_ascii_alphabetic());
assert!(!esc.is_ascii_alphabetic());
Runpub const fn is_ascii_uppercase(&self) -> bool
Checks if the value is an ASCII uppercase character: U+0041 ‘A’ ..= U+005A ‘Z’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(uppercase_a.is_ascii_uppercase());
assert!(uppercase_g.is_ascii_uppercase());
assert!(!a.is_ascii_uppercase());
assert!(!g.is_ascii_uppercase());
assert!(!zero.is_ascii_uppercase());
assert!(!percent.is_ascii_uppercase());
assert!(!space.is_ascii_uppercase());
assert!(!lf.is_ascii_uppercase());
assert!(!esc.is_ascii_uppercase());
Runpub const fn is_ascii_lowercase(&self) -> bool
Checks if the value is an ASCII lowercase character: U+0061 ‘a’ ..= U+007A ‘z’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(!uppercase_a.is_ascii_lowercase());
assert!(!uppercase_g.is_ascii_lowercase());
assert!(a.is_ascii_lowercase());
assert!(g.is_ascii_lowercase());
assert!(!zero.is_ascii_lowercase());
assert!(!percent.is_ascii_lowercase());
assert!(!space.is_ascii_lowercase());
assert!(!lf.is_ascii_lowercase());
assert!(!esc.is_ascii_lowercase());
Runpub const fn is_ascii_alphanumeric(&self) -> bool
Checks if the value is an ASCII alphanumeric character:
- U+0041 ‘A’ ..= U+005A ‘Z’, or
- U+0061 ‘a’ ..= U+007A ‘z’, or
- U+0030 ‘0’ ..= U+0039 ‘9’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(uppercase_a.is_ascii_alphanumeric());
assert!(uppercase_g.is_ascii_alphanumeric());
assert!(a.is_ascii_alphanumeric());
assert!(g.is_ascii_alphanumeric());
assert!(zero.is_ascii_alphanumeric());
assert!(!percent.is_ascii_alphanumeric());
assert!(!space.is_ascii_alphanumeric());
assert!(!lf.is_ascii_alphanumeric());
assert!(!esc.is_ascii_alphanumeric());
Runpub const fn is_ascii_digit(&self) -> bool
Checks if the value is an ASCII decimal digit: U+0030 ‘0’ ..= U+0039 ‘9’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(!uppercase_a.is_ascii_digit());
assert!(!uppercase_g.is_ascii_digit());
assert!(!a.is_ascii_digit());
assert!(!g.is_ascii_digit());
assert!(zero.is_ascii_digit());
assert!(!percent.is_ascii_digit());
assert!(!space.is_ascii_digit());
assert!(!lf.is_ascii_digit());
assert!(!esc.is_ascii_digit());
Runpub const fn is_ascii_hexdigit(&self) -> bool
Checks if the value is an ASCII hexadecimal digit:
- U+0030 ‘0’ ..= U+0039 ‘9’, or
- U+0041 ‘A’ ..= U+0046 ‘F’, or
- U+0061 ‘a’ ..= U+0066 ‘f’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(uppercase_a.is_ascii_hexdigit());
assert!(!uppercase_g.is_ascii_hexdigit());
assert!(a.is_ascii_hexdigit());
assert!(!g.is_ascii_hexdigit());
assert!(zero.is_ascii_hexdigit());
assert!(!percent.is_ascii_hexdigit());
assert!(!space.is_ascii_hexdigit());
assert!(!lf.is_ascii_hexdigit());
assert!(!esc.is_ascii_hexdigit());
Runpub const fn is_ascii_punctuation(&self) -> bool
Checks if the value is an ASCII punctuation character:
- U+0021 ..= U+002F
! " # $ % & ' ( ) * + , - . /
, or - U+003A ..= U+0040
: ; < = > ? @
, or - U+005B ..= U+0060
[ \ ] ^ _ `
, or - U+007B ..= U+007E
{ | } ~
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(!uppercase_a.is_ascii_punctuation());
assert!(!uppercase_g.is_ascii_punctuation());
assert!(!a.is_ascii_punctuation());
assert!(!g.is_ascii_punctuation());
assert!(!zero.is_ascii_punctuation());
assert!(percent.is_ascii_punctuation());
assert!(!space.is_ascii_punctuation());
assert!(!lf.is_ascii_punctuation());
assert!(!esc.is_ascii_punctuation());
Runpub const fn is_ascii_graphic(&self) -> bool
Checks if the value is an ASCII graphic character: U+0021 ‘!’ ..= U+007E ‘~’.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(uppercase_a.is_ascii_graphic());
assert!(uppercase_g.is_ascii_graphic());
assert!(a.is_ascii_graphic());
assert!(g.is_ascii_graphic());
assert!(zero.is_ascii_graphic());
assert!(percent.is_ascii_graphic());
assert!(!space.is_ascii_graphic());
assert!(!lf.is_ascii_graphic());
assert!(!esc.is_ascii_graphic());
Runpub const fn is_ascii_whitespace(&self) -> bool
Checks if the value is an ASCII whitespace character: U+0020 SPACE, U+0009 HORIZONTAL TAB, U+000A LINE FEED, U+000C FORM FEED, or U+000D CARRIAGE RETURN.
Rust uses the WhatWG Infra Standard’s definition of ASCII whitespace. There are several other definitions in wide use. For instance, the POSIX locale includes U+000B VERTICAL TAB as well as all the above characters, but—from the very same specification—the default rule for “field splitting” in the Bourne shell considers only SPACE, HORIZONTAL TAB, and LINE FEED as whitespace.
If you are writing a program that will process an existing file format, check what that format’s definition of whitespace is before using this function.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(!uppercase_a.is_ascii_whitespace());
assert!(!uppercase_g.is_ascii_whitespace());
assert!(!a.is_ascii_whitespace());
assert!(!g.is_ascii_whitespace());
assert!(!zero.is_ascii_whitespace());
assert!(!percent.is_ascii_whitespace());
assert!(space.is_ascii_whitespace());
assert!(lf.is_ascii_whitespace());
assert!(!esc.is_ascii_whitespace());
Runpub const fn is_ascii_control(&self) -> bool
Checks if the value is an ASCII control character: U+0000 NUL ..= U+001F UNIT SEPARATOR, or U+007F DELETE. Note that most ASCII whitespace characters are control characters, but SPACE is not.
Examples
let uppercase_a = 'A';
let uppercase_g = 'G';
let a = 'a';
let g = 'g';
let zero = '0';
let percent = '%';
let space = ' ';
let lf = '\n';
let esc = '\x1b';
assert!(!uppercase_a.is_ascii_control());
assert!(!uppercase_g.is_ascii_control());
assert!(!a.is_ascii_control());
assert!(!g.is_ascii_control());
assert!(!zero.is_ascii_control());
assert!(!percent.is_ascii_control());
assert!(!space.is_ascii_control());
assert!(lf.is_ascii_control());
assert!(esc.is_ascii_control());
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