Returns self.
Returns the receiver. freeze cannot be false.
Returns the absolute value of num.
12.abs #=> 12 (-34.56).abs #=> 34.56 -34.56.abs #=> 34.56
Numeric#magnitude is an alias for Numeric#abs.
Returns self if num is not zero, nil otherwise.
This behavior is useful when chaining comparisons:
a = %w( z Bb bB bb BB a aA Aa AA A ) b = a.sort {|a,b| (a.downcase <=> b.downcase).nonzero? || a <=> b } b #=> ["A", "a", "AA", "Aa", "aA", "BB", "Bb", "bB", "bb", "z"]
Returns true if num is a finite number, otherwise returns false.
Returns nil, -1, or 1 depending on whether the value is finite, -Infinity, or +Infinity.
Splits str into an array of tokens in the same way the UNIX Bourne shell does.
See Shellwords.shellsplit for details.
Decodes str (which may contain binary data) according to the format string, returning an array of each value extracted. The format string consists of a sequence of single-character directives, summarized in the table at the end of this entry. Each directive may be followed by a number, indicating the number of times to repeat with this directive. An asterisk (“*”) will use up all remaining elements. The directives sSiIlL may each be followed by an underscore (“_”) or exclamation mark (“!”) to use the underlying platform’s native size for the specified type; otherwise, it uses a platform-independent consistent size. Spaces are ignored in the format string. See also String#unpack1, Array#pack.
"abc \0\0abc \0\0".unpack('A6Z6') #=> ["abc", "abc "] "abc \0\0".unpack('a3a3') #=> ["abc", " \000\000"] "abc \0abc \0".unpack('Z*Z*') #=> ["abc ", "abc "] "aa".unpack('b8B8') #=> ["10000110", "01100001"] "aaa".unpack('h2H2c') #=> ["16", "61", 97] "\xfe\xff\xfe\xff".unpack('sS') #=> [-2, 65534] "now=20is".unpack('M*') #=> ["now is"] "whole".unpack('xax2aX2aX1aX2a') #=> ["h", "e", "l", "l", "o"]
This table summarizes the various formats and the Ruby classes returned by each.
Integer | |
Directive | Returns | Meaning
------------------------------------------------------------------
C | Integer | 8-bit unsigned (unsigned char)
S | Integer | 16-bit unsigned, native endian (uint16_t)
L | Integer | 32-bit unsigned, native endian (uint32_t)
Q | Integer | 64-bit unsigned, native endian (uint64_t)
J | Integer | pointer width unsigned, native endian (uintptr_t)
| |
c | Integer | 8-bit signed (signed char)
s | Integer | 16-bit signed, native endian (int16_t)
l | Integer | 32-bit signed, native endian (int32_t)
q | Integer | 64-bit signed, native endian (int64_t)
j | Integer | pointer width signed, native endian (intptr_t)
| |
S_ S! | Integer | unsigned short, native endian
I I_ I! | Integer | unsigned int, native endian
L_ L! | Integer | unsigned long, native endian
Q_ Q! | Integer | unsigned long long, native endian (ArgumentError
| | if the platform has no long long type.)
J! | Integer | uintptr_t, native endian (same with J)
| |
s_ s! | Integer | signed short, native endian
i i_ i! | Integer | signed int, native endian
l_ l! | Integer | signed long, native endian
q_ q! | Integer | signed long long, native endian (ArgumentError
| | if the platform has no long long type.)
j! | Integer | intptr_t, native endian (same with j)
| |
S> s> S!> s!> | Integer | same as the directives without ">" except
L> l> L!> l!> | | big endian
I!> i!> | |
Q> q> Q!> q!> | | "S>" is same as "n"
J> j> J!> j!> | | "L>" is same as "N"
| |
S< s< S!< s!< | Integer | same as the directives without "<" except
L< l< L!< l!< | | little endian
I!< i!< | |
Q< q< Q!< q!< | | "S<" is same as "v"
J< j< J!< j!< | | "L<" is same as "V"
| |
n | Integer | 16-bit unsigned, network (big-endian) byte order
N | Integer | 32-bit unsigned, network (big-endian) byte order
v | Integer | 16-bit unsigned, VAX (little-endian) byte order
V | Integer | 32-bit unsigned, VAX (little-endian) byte order
| |
U | Integer | UTF-8 character
w | Integer | BER-compressed integer (see Array#pack)
Float | |
Directive | Returns | Meaning
-----------------------------------------------------------------
D d | Float | double-precision, native format
F f | Float | single-precision, native format
E | Float | double-precision, little-endian byte order
e | Float | single-precision, little-endian byte order
G | Float | double-precision, network (big-endian) byte order
g | Float | single-precision, network (big-endian) byte order
String | |
Directive | Returns | Meaning
-----------------------------------------------------------------
A | String | arbitrary binary string (remove trailing nulls and ASCII spaces)
a | String | arbitrary binary string
Z | String | null-terminated string
B | String | bit string (MSB first)
b | String | bit string (LSB first)
H | String | hex string (high nibble first)
h | String | hex string (low nibble first)
u | String | UU-encoded string
M | String | quoted-printable, MIME encoding (see RFC2045)
m | String | base64 encoded string (RFC 2045) (default)
| | base64 encoded string (RFC 4648) if followed by 0
P | String | pointer to a structure (fixed-length string)
p | String | pointer to a null-terminated string
Misc. | |
Directive | Returns | Meaning
-----------------------------------------------------------------
@ | --- | skip to the offset given by the length argument
X | --- | skip backward one byte
x | --- | skip forward one byte
HISTORY
J, J! j, and j! are available since Ruby 2.3.
Q_, Q!, q_, and q! are available since Ruby 2.1.
I!<, i!<, I!>, and i!> are available since Ruby 1.9.3.
Decodes str (which may contain binary data) according to the format string, returning the first value extracted. See also String#unpack, Array#pack.
Contrast with String#unpack:
"abc \0\0abc \0\0".unpack('A6Z6') #=> ["abc", "abc "] "abc \0\0abc \0\0".unpack1('A6Z6') #=> "abc"
In that case data would be lost but often it’s the case that the array only holds one value, especially when unpacking binary data. For instance:
“xffx00x00x00”.unpack(“l”) #=> [255] “xffx00x00x00”.unpack1(“l”) #=> 255
Thus unpack1 is convenient, makes clear the intention and signals the expected return value to those reading the code.
Inserts the given other_string into self; returns self.
If the Integer index is positive, inserts other_string at offset index:
'foo'.insert(1, 'bar') # => "fbaroo"
If the Integer index is negative, counts backward from the end of self and inserts other_string at offset index+1 (that is, after self[index]):
'foo'.insert(-2, 'bar') # => "fobaro"
Returns a copy of str with the first character converted to uppercase and the remainder to lowercase.
See String#downcase for meaning of options and use with different encodings.
"hello".capitalize #=> "Hello" "HELLO".capitalize #=> "Hello" "123ABC".capitalize #=> "123abc"
Modifies str by converting the first character to uppercase and the remainder to lowercase. Returns nil if no changes are made. There is an exception for modern Georgian (mkhedruli/MTAVRULI), where the result is the same as for String#downcase, to avoid mixed case.
See String#downcase for meaning of options and use with different encodings.
a = "hello" a.capitalize! #=> "Hello" a #=> "Hello" a.capitalize! #=> nil
Divides str into substrings based on a delimiter, returning an array of these substrings.
If pattern is a String, then its contents are used as the delimiter when splitting str. If pattern is a single space, str is split on whitespace, with leading and trailing whitespace and runs of contiguous whitespace characters ignored.
If pattern is a Regexp, str is divided where the pattern matches. Whenever the pattern matches a zero-length string, str is split into individual characters. If pattern contains groups, the respective matches will be returned in the array as well.
If pattern is nil, the value of $; is used. If $; is nil (which is the default), str is split on whitespace as if ‘ ’ were specified.
If the limit parameter is omitted, trailing null fields are suppressed. If limit is a positive number, at most that number of split substrings will be returned (captured groups will be returned as well, but are not counted towards the limit). If limit is 1, the entire string is returned as the only entry in an array. If negative, there is no limit to the number of fields returned, and trailing null fields are not suppressed.
When the input str is empty an empty Array is returned as the string is considered to have no fields to split.
" now's the time ".split #=> ["now's", "the", "time"] " now's the time ".split(' ') #=> ["now's", "the", "time"] " now's the time".split(/ /) #=> ["", "now's", "", "the", "time"] "1, 2.34,56, 7".split(%r{,\s*}) #=> ["1", "2.34", "56", "7"] "hello".split(//) #=> ["h", "e", "l", "l", "o"] "hello".split(//, 3) #=> ["h", "e", "llo"] "hi mom".split(%r{\s*}) #=> ["h", "i", "m", "o", "m"] "mellow yellow".split("ello") #=> ["m", "w y", "w"] "1,2,,3,4,,".split(',') #=> ["1", "2", "", "3", "4"] "1,2,,3,4,,".split(',', 4) #=> ["1", "2", "", "3,4,,"] "1,2,,3,4,,".split(',', -4) #=> ["1", "2", "", "3", "4", "", ""] "1:2:3".split(/(:)()()/, 2) #=> ["1", ":", "", "", "2:3"] "".split(',', -1) #=> []
If a block is given, invoke the block with each split substring.
Returns an array of characters in str. This is a shorthand for str.each_char.to_a.
If a block is given, which is a deprecated form, works the same as each_char.
Concatenates each object in objects to self and returns self:
s = 'foo' s.concat('bar', 'baz') # => "foobarbaz" s # => "foobarbaz"
For each given object object that is an Integer, the value is considered a codepoint and converted to a character before concatenation:
s = 'foo' s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"
Related: String#<<, which takes a single argument.
Returns 0 if the value is positive, pi otherwise.
Returns the absolute value of float.
(-34.56).abs #=> 34.56 -34.56.abs #=> 34.56 34.56.abs #=> 34.56
Float#magnitude is an alias for Float#abs.
Returns nil, -1, or 1 depending on whether the value is finite, -Infinity, or +Infinity.
(0.0).infinite? #=> nil (-1.0/0.0).infinite? #=> -1 (+1.0/0.0).infinite? #=> 1
Returns true if float is a valid IEEE floating point number, i.e. it is not infinite and Float#nan? is false.
Returns the real (absolute) pathname of pathname in the actual filesystem not containing symlinks or useless dots.
If dir_string is given, it is used as a base directory for interpreting relative pathname instead of the current directory.
All components of the pathname must exist when this method is called.
Returns the real (absolute) pathname of pathname in the actual filesystem. The real pathname doesn’t contain symlinks or useless dots.
If dir_string is given, it is used as a base directory for interpreting relative pathname instead of the current directory.
The last component of the real pathname can be nonexistent.
Returns the string representation of the path
File.path("/dev/null") #=> "/dev/null" File.path(Pathname.new("/tmp")) #=> "/tmp"