A Char
represents a Unicode code point. It occupies 32 bits.
It is created by enclosing an UTF-8 character in single quotes.
'a' 'z' '0' '_' 'あ'
You can use a backslash to denote some characters:
'\'' # single quote '\\' # backslash '\e' # escape '\f' # form feed '\n' # newline '\r' # carriage return '\t' # tab '\v' # vertical tab
You can use a backslash followed by an u and four hexadecimal characters to denote a unicode codepoint written:
'\u0041' # == 'A'
Or you can use curly braces and specify up to four hexadecimal numbers:
'\u{41}' # == 'A'
1114111.unsafe_chr
The maximum character.
1114111
The maximum valid codepoint for a character.
'�'
The replacement character, used on invalid UTF-8 byte sequences.
'\u{0}'
The character representing the end of a C string.
Returns true
if self
's codepoint is not equal to other's codepoint.
Concatenates this char and string.
Returns a char that has this char's codepoint plus other.
Returns the difference of the codepoint values of this char and other.
Returns a char that has this char's codepoint minus other.
Returns true
if self
's codepoint is less than other's codepoint.
Returns true
if self
's codepoint is less than or equal to other's codepoint.
The comparison operator.
Returns true
if self
's codepoint is equal to other's codepoint.
Returns true
if the codepoint is equal to byte ignoring the type.
Returns true
if self
's codepoint is greater than other's codepoint.
Returns true
if self
's codepoint is greater than or equal to other's codepoint.
Returns true
if this char is a letter or a number according to unicode.
Returns true
if this char is an ASCII character (codepoint is in (0..127))
Returns true
if this char is an ASCII letter or number ('0' to '9', 'a' to 'z', 'A' to 'Z').
Returns true
if this char is an ASCII control character.
Returns true
if this char is an ASCII letter ('a' to 'z', 'A' to 'Z').
Returns true
if this char is a lowercase ASCII letter.
Returns true
if this char is an ASCII number in specified base.
Returns true
if this char is an ASCII uppercase letter.
Returns true
if this char is an ASCII whitespace.
Returns the number of UTF-8 bytes in this char.
Returns true
if this char is a control character according to unicode.
Returns the downcase equivalent of this char.
Yields each char for the downcase equivalent of this char.
Returns this char as a string that contains a char literal as written in Crystal, with characters with a codepoint greater than 0x79
written as \u{...}
.
Appends this char as a string that contains a char literal to the given IO
.
Yields each of the bytes of this char as encoded by UTF-8.
Returns true
if this char is an ASCII hex digit ('0' to '9', 'a' to 'f', 'A' to 'F').
Returns true
if this char is matched by the given sets.
Returns this char as a string that contains a char literal.
Appends this char as a string that contains a char literal to the given IO
.
Returns true
if this char is a letter.
Returns true
if this char is a lowercase letter.
Returns true
if this is char is a mark character according to unicode.
Returns true
if this char is a number according to unicode.
Returns the codepoint of this char.
Returns a Char that is one codepoint smaller than this char's codepoint.
Returns a Char that is one codepoint bigger than this char's codepoint.
Returns the integer value of this char as a float if it's an ASCII char denoting a digit, raises otherwise.
See also: #to_f
.
See also: #to_f?
.
Same as #to_f
.
Same as #to_f?
.
Returns the integer value of this char as a float if it's an ASCII char denoting a digit, nil
otherwise.
Returns the integer value of this char if it's an ASCII char denoting a digit in base, raises otherwise.
See also: #to_i
.
See also: #to_i?
.
Same as #to_i
.
Same as #to_i?
.
See also: #to_i
.
See also: #to_i?
.
See also: #to_i
.
See also: #to_i?
.
Returns the integer value of this char if it's an ASCII char denoting a digit in base, nil
otherwise.
Returns this char as a string containing this char as a single character.
Appends this char to the given IO
.
See also: #to_i
.
See also: #to_i?
.
See also: #to_i
.
See also: #to_i?
.
See also: #to_i
.
See also: #to_i?
.
See also: #to_i
.
See also: #to_i?
.
Yields each char for the upcase equivalent of this char.
Returns the upcase equivalent of this char.
Returns true
if this char is an uppercase letter.
Returns true
if this char is a whitespace according to unicode.
Comparable(Char)
Value
Object
Object
Returns true
if self
's codepoint is not equal to other's codepoint.
Returns a char that has this char's codepoint plus other.
'a' + 1 # => 'b' 'a' + 2 # => 'c'
Returns the difference of the codepoint values of this char and other.
'a' - 'a' # => 0 'b' - 'a' # => 1 'c' - 'a' # => 2
Returns a char that has this char's codepoint minus other.
'c' - 1 # => 'b' 'c' - 2 # => 'a'
Returns true
if self
's codepoint is less than or equal to other's codepoint.
The comparison operator.
Returns the difference of the codepoint values of self
and other. The result is either negative, 0
or positive based on whether other
's codepoint is less, equal, or greater than self
's codepoint.
'a' <=> 'c' # => -2 'z' <=> 'z' # => 0 'c' <=> 'a' # => 2
Returns true
if the codepoint is equal to byte ignoring the type.
'c'.ord # => 99 'c' === 99_u8 # => true 'c' === 99 # => true 'z' === 99 # => false
Returns true
if self
's codepoint is greater than other's codepoint.
Returns true
if self
's codepoint is greater than or equal to other's codepoint.
Returns true
if this char is a letter or a number according to unicode.
'c'.alphanumeric? # => true '8'.alphanumeric? # => true '.'.alphanumeric? # => false
Returns true
if this char is an ASCII character (codepoint is in (0..127))
Returns true
if this char is an ASCII letter or number ('0' to '9', 'a' to 'z', 'A' to 'Z').
'c'.ascii_alphanumeric? # => true '8'.ascii_alphanumeric? # => true '.'.ascii_alphanumeric? # => false
Returns true
if this char is an ASCII control character.
('\u0000'..'\u0019').each do |char| char.control? # => true end ('\u007F'..'\u009F').each do |char| char.control? # => true end
Returns true
if this char is an ASCII letter ('a' to 'z', 'A' to 'Z').
'c'.ascii_letter? # => true 'á'.ascii_letter? # => false '8'.ascii_letter? # => false
Returns true
if this char is a lowercase ASCII letter.
'c'.ascii_lowercase? # => true 'ç'.lowercase? # => true 'G'.ascii_lowercase? # => false '.'.ascii_lowercase? # => false
Returns true
if this char is an ASCII number in specified base.
Base can be from 0 to 36 with digits from '0' to '9' and 'a' to 'z' or 'A' to 'Z'.
'4'.ascii_number? # => true 'z'.ascii_number? # => false 'z'.ascii_number?(36) # => true
Returns true
if this char is an ASCII uppercase letter.
'H'.ascii_uppercase? # => true 'Á'.ascii_uppercase? # => false 'c'.ascii_uppercase? # => false '.'.ascii_uppercase? # => false
Returns true
if this char is an ASCII whitespace.
' '.ascii_whitespace? # => true '\t'.ascii_whitespace? # => true 'b'.ascii_whitespace? # => false
Returns the number of UTF-8 bytes in this char.
'a'.bytesize # => 1 '好'.bytesize # => 3
Returns true
if this char is a control character according to unicode.
Returns the downcase equivalent of this char.
Note that this only works for characters whose downcase equivalent yields a single codepoint. There are a few characters, like 'İ', than when downcased result in multiple characters (in this case: 'I' and the dot mark).
For a more correct method see the method that receives a block.
'Z'.downcase # => 'z' 'x'.downcase # => 'x' '.'.downcase # => '.'
Yields each char for the downcase equivalent of this char.
This method takes into account the possibility that an downcase version of a char might result in multiple chars, like for 'İ', which results in 'i' and a dot mark.
Returns this char as a string that contains a char literal as written in Crystal, with characters with a codepoint greater than 0x79
written as \u{...}
.
'a'.dump # => "'a'" '\t'.dump # => "'\\t'" 'あ'.dump # => "'\\u{3042}'" '\u0012'.dump # => "'\\u{12}'"
Yields each of the bytes of this char as encoded by UTF-8.
puts "'a'" 'a'.each_byte do |byte| puts byte end puts puts "'あ'" 'あ'.each_byte do |byte| puts byte end
Output:
'a' 97 'あ' 227 129 130
Returns true
if this char is an ASCII hex digit ('0' to '9', 'a' to 'f', 'A' to 'F').
'5'.hex? # => true 'a'.hex? # => true 'F'.hex? # => true 'g'.hex? # => false
Returns true
if this char is matched by the given sets.
Each parameter defines a set, the character is matched against the intersection of those, in other words it needs to match all sets.
If a set starts with a ^, it is negated. The sequence c1-c2 means all characters between and including c1 and c2 and is known as a range.
The backslash character \ can be used to escape ^ or - and is otherwise ignored unless it appears at the end of a range or set.
'l'.in_set? "lo" # => true 'l'.in_set? "lo", "o" # => false 'l'.in_set? "hello", "^l" # => false 'l'.in_set? "j-m" # => true '^'.in_set? "\\^aeiou" # => true '-'.in_set? "a\\-eo" # => true '\\'.in_set? "\\" # => true '\\'.in_set? "\\A" # => false '\\'.in_set? "X-\\w" # => true
Returns this char as a string that contains a char literal.
'a'.inspect # => "'a'" '\t'.inspect # => "'\\t'" 'あ'.inspect # => "'あ'" '\u0012'.inspect # => "'\\u{12}'"
Returns true
if this char is a letter.
'c'.letter? # => true 'á'.letter? # => true '8'.letter? # => false
Returns true
if this char is a lowercase letter.
'c'.lowercase? # => true 'ç'.lowercase? # => true 'G'.lowercase? # => false '.'.lowercase? # => false
Returns true
if this is char is a mark character according to unicode.
Returns true
if this char is a number according to unicode.
'1'.number? # => true 'a'.number? # => false
Returns the codepoint of this char.
The codepoint is the integer representation. The Universal Coded Character Set (UCS) standard, commonly known as Unicode, assigns names and meanings to numbers, these numbers are called codepoints.
For values below and including 127 this matches the ASCII codes and thus its byte representation.
'a'.ord # => 97 '\0'.ord # => 0 '\u007f'.ord # => 127 '☃'.ord # => 9731
Returns a Char that is one codepoint smaller than this char's codepoint.
'b'.pred # => 'a' 'ぃ'.pred # => 'あ'
Returns a Char that is one codepoint bigger than this char's codepoint.
'a'.succ # => 'b' 'あ'.succ # => 'ぃ'
This method allows creating a Range
of chars.
Returns the integer value of this char as a float if it's an ASCII char denoting a digit, raises otherwise.
'1'.to_f # => 1.0 '8'.to_f # => 8.0 'c'.to_f # raises ArgumentError
Returns the integer value of this char as a float if it's an ASCII char denoting a digit, nil
otherwise.
'1'.to_f? # => 1.0 '8'.to_f? # => 8.0 'c'.to_f? # => nil
Returns the integer value of this char if it's an ASCII char denoting a digit in base, raises otherwise.
'1'.to_i # => 1 '8'.to_i # => 8 'c'.to_i # raises ArgumentError '1'.to_i(16) # => 1 'a'.to_i(16) # => 10 'f'.to_i(16) # => 15 'z'.to_i(16) # raises ArgumentError
Returns the integer value of this char if it's an ASCII char denoting a digit in base, nil
otherwise.
'1'.to_i? # => 1 '8'.to_i? # => 8 'c'.to_i? # => nil '1'.to_i?(16) # => 1 'a'.to_i?(16) # => 10 'f'.to_i?(16) # => 15 'z'.to_i?(16) # => nil
Returns this char as a string containing this char as a single character.
'a'.to_s # => "a" 'あ'.to_s # => "あ"
Yields each char for the upcase equivalent of this char.
This method takes into account the possibility that an upcase version of a char might result in multiple chars, like for 'ffl', which results in 'F', 'F' and 'L'.
'z'.upcase { |v| puts v } # prints 'Z' 'ffl'.upcase { |v| puts v } # prints 'F', 'F', 'L'
Returns the upcase equivalent of this char.
Note that this only works for characters whose upcase equivalent yields a single codepoint. There are a few characters, like 'ffl', than when upcased result in multiple characters (in this case: 'F', 'F', 'L').
For a more correct method see the method that receives a block.
'z'.upcase # => 'Z' 'X'.upcase # => 'X' '.'.upcase # => '.'
Returns true
if this char is an uppercase letter.
'H'.uppercase? # => true 'Á'.uppercase? # => true 'c'.uppercase? # => false '.'.uppercase? # => false
Returns true
if this char is a whitespace according to unicode.
' '.whitespace? # => true '\t'.whitespace? # => true 'b'.whitespace? # => false
© 2012–2020 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/0.35.1/Char.html