1.0.0[]Primitive Type char

A character type.

The char type represents a single character. More specifically, since 'character' isn't a well-defined concept in Unicode, char is a 'Unicode scalar value', which is similar to, but not the same as, a 'Unicode code point'.

This documentation describes a number of methods and trait implementations on the char type. For technical reasons, there is additional, separate documentation in the std::char module as well.

Representation

char is always four bytes in size. This is a different representation than a given character would have as part of a String. For example:

let v = vec!['h', 'e', 'l', 'l', 'o'];

// five elements times four bytes for each element
assert_eq!(20, v.len() * std::mem::size_of::<char>());

let s = String::from("hello");

// five elements times one byte per element
assert_eq!(5, s.len() * std::mem::size_of::<u8>());
Run

As always, remember that a human intuition for 'character' may not map to Unicode's definitions. For example, despite looking similar, the 'é' character is one Unicode code point while 'é' is two Unicode code points:

let mut chars = "é".chars();
// U+00e9: 'latin small letter e with acute'
assert_eq!(Some('\u{00e9}'), chars.next());
assert_eq!(None, chars.next());

let mut chars = "é".chars();
// U+0065: 'latin small letter e'
assert_eq!(Some('\u{0065}'), chars.next());
// U+0301: 'combining acute accent'
assert_eq!(Some('\u{0301}'), chars.next());
assert_eq!(None, chars.next());
Run

This means that the contents of the first string above will fit into a char while the contents of the second string will not. Trying to create a char literal with the contents of the second string gives an error:

error: character literal may only contain one codepoint: 'é'
let c = 'é';
        ^^^

Another implication of the 4-byte fixed size of a char is that per-char processing can end up using a lot more memory:

let s = String::from("love: ❤️");
let v: Vec<char> = s.chars().collect();

assert_eq!(12, std::mem::size_of_val(&s[..]));
assert_eq!(32, std::mem::size_of_val(&v[..]));
Run

Implementations

impl char[src]

pub const MAX: char[src]

🔬 This is a nightly-only experimental API. (assoc_char_consts #71763)

recently added

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.

pub const REPLACEMENT_CHARACTER: char[src]

🔬 This is a nightly-only experimental API. (assoc_char_consts #71763)

recently added

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.

pub const UNICODE_VERSION: (u8, u8, u8)[src]

🔬 This is a nightly-only experimental API. (assoc_char_consts #71763)

recently added

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.

pub fn decode_utf16<I>(iter: I) -> DecodeUtf16<<I as IntoIterator>::IntoIter>

Important traits for DecodeUtf16<I>

impl<I> Iterator for DecodeUtf16<I> where
    I: Iterator<Item = u16>, 
type Item = Result<char, DecodeUtf16Error>;
where
    I: IntoIterator<Item = u16>, 
[src]

🔬 This is a nightly-only experimental API. (assoc_char_funcs #71763)

recently added

Creates an iterator over the UTF-16 encoded code points in iter, returning unpaired surrogates as Errs.

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.iter().cloned())
        .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)
    ]
);
Run

A 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.iter().cloned())
       .map(|r| r.unwrap_or(REPLACEMENT_CHARACTER))
       .collect::<String>(),
    "𝄞mus�ic�"
);
Run

pub fn from_u32(i: u32) -> Option<char>[src]

🔬 This is a nightly-only experimental API. (assoc_char_funcs #71763)

recently added

Converts a u32 to a char.

Note that all chars are valid u32s, and can be cast to one with as:

let c = '💯';
let i = c as u32;

assert_eq!(128175, i);
Run

However, the reverse is not true: not all valid u32s are valid chars. 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);
Run

Returning None when the input is not a valid char:

use std::char;

let c = char::from_u32(0x110000);

assert_eq!(None, c);
Run

pub unsafe fn from_u32_unchecked(i: u32) -> char[src]

🔬 This is a nightly-only experimental API. (assoc_char_funcs #71763)

recently added

Converts a u32 to a char, ignoring validity.

Note that all chars are valid u32s, and can be cast to one with as:

let c = '💯';
let i = c as u32;

assert_eq!(128175, i);
Run

However, the reverse is not true: not all valid u32s are valid chars. 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);
Run

pub fn from_digit(num: u32, radix: u32) -> Option<char>[src]

🔬 This is a nightly-only experimental API. (assoc_char_funcs #71763)

recently added

Converts 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);
Run

Returning None when the input is not a digit:

use std::char;

let c = char::from_digit(20, 10);

assert_eq!(None, c);
Run

Passing a large radix, causing a panic:

This example panics
use std::char;

// this panics
char::from_digit(1, 37);
Run

pub fn is_digit(self, radix: u32) -> bool[src]

Checks 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));
Run

Passing a large radix, causing a panic:

This example panics
// this panics
'1'.is_digit(37);
Run

pub fn to_digit(self, radix: u32) -> Option<u32>[src]

Converts 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));
Run

Passing a non-digit results in failure:

assert_eq!('f'.to_digit(10), None);
assert_eq!('z'.to_digit(16), None);
Run

Passing a large radix, causing a panic:

This example panics
// this panics
'1'.to_digit(37);
Run

pub fn escape_unicode(self) -> EscapeUnicode

Important traits for EscapeUnicode

impl Iterator for EscapeUnicode type Item = char;
[src]

Returns an iterator that yields the hexadecimal Unicode escape of a character as chars.

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!();
Run

Using println! directly:

println!("{}", '❤'.escape_unicode());
Run

Both are equivalent to:

println!("\\u{{2764}}");
Run

Using to_string:

assert_eq!('❤'.escape_unicode().to_string(), "\\u{2764}");
Run

pub fn escape_debug(self) -> EscapeDebug

Important traits for EscapeDebug

impl Iterator for EscapeDebug type Item = char;
1.20.0[src]

Returns an iterator that yields the literal escape code of a character as chars.

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!();
Run

Using println! directly:

println!("{}", '\n'.escape_debug());
Run

Both are equivalent to:

println!("\\n");
Run

Using to_string:

assert_eq!('\n'.escape_debug().to_string(), "\\n");
Run

pub fn escape_default(self) -> EscapeDefault

Important traits for EscapeDefault

impl Iterator for EscapeDefault type Item = char;
[src]

Returns an iterator that yields the literal escape code of a character as chars.

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!();
Run

Using println! directly:

println!("{}", '"'.escape_default());
Run

Both are equivalent to:

println!("\\\"");
Run

Using to_string:

assert_eq!('"'.escape_default().to_string(), "\\\"");
Run

pub fn len_utf8(self) -> usize[src]

Returns 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);
Run

The &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());
Run

pub fn len_utf16(self) -> usize[src]

Returns 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);
Run

pub fn encode_utf8(self, dst: &mut [u8]) -> &mut str1.15.0[src]

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);
Run

A buffer that's too small:

This example panics
let mut b = [0; 1];

// this panics
'ß'.encode_utf8(&mut b);
Run

pub fn encode_utf16(self, dst: &mut [u16]) -> &mut [u16]

Important traits for &'_ [u8]

impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
1.15.0[src]

Encodes 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 u16s to encode.

let mut b = [0; 2];

let result = '𝕊'.encode_utf16(&mut b);

assert_eq!(result.len(), 2);
Run

A buffer that's too small:

This example panics
let mut b = [0; 1];

// this panics
'𝕊'.encode_utf16(&mut b);
Run

pub fn is_alphabetic(self) -> bool[src]

Returns 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());
Run

pub fn is_lowercase(self) -> bool[src]

Returns 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());
Run

pub fn is_uppercase(self) -> bool[src]

Returns 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());
Run

pub fn is_whitespace(self) -> bool[src]

Returns 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());
Run

pub fn is_alphanumeric(self) -> bool[src]

Returns 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());
Run

pub fn is_control(self) -> bool[src]

Returns 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!('œ'.is_control());
assert!(!'q'.is_control());
Run

pub fn is_numeric(self) -> bool[src]

Returns 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());
Run

pub fn to_lowercase(self) -> ToLowercase

Important traits for ToLowercase

impl Iterator for ToLowercase type Item = char;
[src]

Returns an iterator that yields the lowercase mapping of this char as one or more chars.

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 chars) 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!();
Run

Using println! directly:

println!("{}", 'İ'.to_lowercase());
Run

Both are equivalent to:

println!("i\u{307}");
Run

Using 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");
Run

pub fn to_uppercase(self) -> ToUppercase

Important traits for ToUppercase

impl Iterator for ToUppercase type Item = char;
[src]

Returns an iterator that yields the uppercase mapping of this char as one or more chars.

If this char does not have a 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 chars) 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!();
Run

Using println! directly:

println!("{}", 'ß'.to_uppercase());
Run

Both are equivalent to:

println!("SS");
Run

Using 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");
Run

Note 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();
Run

The 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");
Run

holds across languages.

pub const fn is_ascii(&self) -> bool1.23.0[src]

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());
Run

pub fn to_ascii_uppercase(&self) -> char1.23.0[src]

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());
Run

pub fn to_ascii_lowercase(&self) -> char1.23.0[src]

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());
Run

pub fn eq_ignore_ascii_case(&self, other: &char) -> bool1.23.0[src]

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));
Run

pub fn make_ascii_uppercase(&mut self)1.23.0[src]

Converts 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);
Run

pub fn make_ascii_lowercase(&mut self)1.23.0[src]

Converts 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);
Run

pub fn is_ascii_alphabetic(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_uppercase(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_lowercase(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_alphanumeric(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_digit(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_hexdigit(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_punctuation(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_graphic(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_whitespace(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

pub fn is_ascii_control(&self) -> bool1.24.0[src]

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: char = 0x1b_u8.into();

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());
Run

Trait Implementations

impl AsciiExt for char[src]

type Owned = char

👎 Deprecated since 1.26.0:

use inherent methods instead

Container type for copied ASCII characters.

impl Clone for char[src]

impl Copy for char[src]

impl Debug for char[src]

impl Default for char[src]

fn default() -> char[src]

Returns the default value of \x00

impl Display for char[src]

impl Eq for char[src]

impl From<u8> for char1.13.0[src]

Maps a byte in 0x00..=0xFF to a char whose code point has the same value, in U+0000..=U+00FF.

Unicode is designed such that this effectively decodes bytes with the character encoding that IANA calls ISO-8859-1. This encoding is compatible with ASCII.

Note that this is different from ISO/IEC 8859-1 a.k.a. ISO 8859-1 (with one less hyphen), which leaves some "blanks", byte values that are not assigned to any character. ISO-8859-1 (the IANA one) assigns them to the C0 and C1 control codes.

Note that this is also different from Windows-1252 a.k.a. code page 1252, which is a superset ISO/IEC 8859-1 that assigns some (not all!) blanks to punctuation and various Latin characters.

To confuse things further, on the Web ascii, iso-8859-1, and windows-1252 are all aliases for a superset of Windows-1252 that fills the remaining blanks with corresponding C0 and C1 control codes.

fn from(i: u8) -> char[src]

Converts a u8 into a char.

Examples

use std::mem;

let u = 32 as u8;
let c = char::from(u);
assert!(4 == mem::size_of_val(&c))
Run

impl FromStr for char1.20.0[src]

type Err = ParseCharError

The associated error which can be returned from parsing.

impl Hash for char[src]

impl Ord for char[src]

impl PartialEq<char> for char[src]

impl PartialOrd<char> for char[src]

impl ToString for char1.46.0[src]

impl TryFrom<u32> for char1.34.0[src]

type Error = CharTryFromError

The type returned in the event of a conversion error.

Auto Trait Implementations

impl RefUnwindSafe for char

impl Send for char

impl Sync for char

impl Unpin for char

impl UnwindSafe for char

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<'a, F> Pattern<'a> for F where
    F: FnMut(char) -> bool
[src]

type Searcher = CharPredicateSearcher<'a, F>

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Associated searcher for this pattern

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.

impl<T> ToString for T where
    T: Display + ?Sized
[src]

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.