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 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) #=> []
Returns an array of bytes in str. This is a shorthand for str.each_byte.to_a.
If a block is given, which is a deprecated form, works the same as each_byte.
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.
Returns a new string with the characters from str in reverse order.
"stressed".reverse #=> "desserts"
Reverses str in place.
Concatenates the given object(s) to str. If an object is an Integer, it is considered a codepoint and converted to a character before concatenation.
concat can take multiple arguments, and all the arguments are concatenated in order.
a = "hello " a.concat("world", 33) #=> "hello world!" a #=> "hello world!" b = "sn" b.concat("_", b, "_", b) #=> "sn_sn_sn"
See also String#<<, which takes a single argument.
Appends the given object to str. If the object is an Integer, it is considered a codepoint and converted to a character before being appended.
a = "hello " a << "world" #=> "hello world" a << 33 #=> "hello world!"
See also String#concat, which takes multiple arguments.
Prepend—Prepend the given strings to str.
a = "!" a.prepend("hello ", "world") #=> "hello world!" a #=> "hello world!"
See also String#concat.
Applies a one-way cryptographic hash to str by invoking the standard library function crypt(3) with the given salt string. While the format and the result are system and implementation dependent, using a salt matching the regular expression \A[a-zA-Z0-9./]{2} should be valid and safe on any platform, in which only the first two characters are significant.
This method is for use in system specific scripts, so if you want a cross-platform hash function consider using Digest or OpenSSL instead.
Both forms iterate through str, matching the pattern (which may be a Regexp or a String). For each match, a result is generated and either added to the result array or passed to the block. If the pattern contains no groups, each individual result consists of the matched string, $&. If the pattern contains groups, each individual result is itself an array containing one entry per group.
a = "cruel world" a.scan(/\w+/) #=> ["cruel", "world"] a.scan(/.../) #=> ["cru", "el ", "wor"] a.scan(/(...)/) #=> [["cru"], ["el "], ["wor"]] a.scan(/(..)(..)/) #=> [["cr", "ue"], ["l ", "wo"]]
And the block form:
a.scan(/\w+/) {|w| print "<<#{w}>> " } print "\n" a.scan(/(.)(.)/) {|x,y| print y, x } print "\n"
produces:
<<cruel>> <<world>> rceu lowlr
Centers str in width. If width is greater than the length of str, returns a new String of length width with str centered and padded with padstr; otherwise, returns str.
"hello".center(4) #=> "hello" "hello".center(20) #=> " hello " "hello".center(20, '123') #=> "1231231hello12312312"
Returns a copy of str with the first occurrence of pattern replaced by the second argument. The pattern is typically a Regexp; if given as a String, any regular expression metacharacters it contains will be interpreted literally, e.g. '\\d' will match a backslash followed by ‘d’, instead of a digit.
If replacement is a String it will be substituted for the matched text. It may contain back-references to the pattern’s capture groups of the form "\d", where d is a group number, or "\k<n>", where n is a group name. If it is a double-quoted string, both back-references must be preceded by an additional backslash. However, within replacement the special match variables, such as $&, will not refer to the current match. If replacement is a String that looks like a pattern’s capture group but is actually not a pattern capture group e.g. "\'", then it will have to be preceded by two backslashes like so "\\'".
If the second argument is a Hash, and the matched text is one of its keys, the corresponding value is the replacement string.
In the block form, the current match string is passed in as a parameter, and variables such as $1, $2, $`, $&, and $' will be set appropriately. The value returned by the block will be substituted for the match on each call.
The result inherits any tainting in the original string or any supplied replacement string.
"hello".sub(/[aeiou]/, '*') #=> "h*llo" "hello".sub(/([aeiou])/, '<\1>') #=> "h<e>llo" "hello".sub(/./) {|s| s.ord.to_s + ' ' } #=> "104 ello" "hello".sub(/(?<foo>[aeiou])/, '*\k<foo>*') #=> "h*e*llo" 'Is SHELL your preferred shell?'.sub(/[[:upper:]]{2,}/, ENV) #=> "Is /bin/bash your preferred shell?"
Returns a copy of str with all occurrences of pattern substituted for the second argument. The pattern is typically a Regexp; if given as a String, any regular expression metacharacters it contains will be interpreted literally, e.g. '\\d' will match a backslash followed by ‘d’, instead of a digit.
If replacement is a String it will be substituted for the matched text. It may contain back-references to the pattern’s capture groups of the form \\d, where d is a group number, or \\k<n>, where n is a group name. If it is a double-quoted string, both back-references must be preceded by an additional backslash. However, within replacement the special match variables, such as $&, will not refer to the current match.
If the second argument is a Hash, and the matched text is one of its keys, the corresponding value is the replacement string.
In the block form, the current match string is passed in as a parameter, and variables such as $1, $2, $`, $&, and $' will be set appropriately. The value returned by the block will be substituted for the match on each call.
The result inherits any tainting in the original string or any supplied replacement string.
When neither a block nor a second argument is supplied, an Enumerator is returned.
"hello".gsub(/[aeiou]/, '*') #=> "h*ll*" "hello".gsub(/([aeiou])/, '<\1>') #=> "h<e>ll<o>" "hello".gsub(/./) {|s| s.ord.to_s + ' '} #=> "104 101 108 108 111 " "hello".gsub(/(?<foo>[aeiou])/, '{\k<foo>}') #=> "h{e}ll{o}" 'hello'.gsub(/[eo]/, 'e' => 3, 'o' => '*') #=> "h3ll*"
Returns a new String with the last character removed. If the string ends with \r\n, both characters are removed. Applying chop to an empty string returns an empty string. String#chomp is often a safer alternative, as it leaves the string unchanged if it doesn’t end in a record separator.
"string\r\n".chop #=> "string" "string\n\r".chop #=> "string\n" "string\n".chop #=> "string" "string".chop #=> "strin" "x".chop.chop #=> ""
Returns a new String with the given record separator removed from the end of str (if present). If $/ has not been changed from the default Ruby record separator, then chomp also removes carriage return characters (that is it will remove \n, \r, and \r\n). If $/ is an empty string, it will remove all trailing newlines from the string.
"hello".chomp #=> "hello" "hello\n".chomp #=> "hello" "hello\r\n".chomp #=> "hello" "hello\n\r".chomp #=> "hello\n" "hello\r".chomp #=> "hello" "hello \n there".chomp #=> "hello \n there" "hello".chomp("llo") #=> "he" "hello\r\n\r\n".chomp('') #=> "hello" "hello\r\n\r\r\n".chomp('') #=> "hello\r\n\r"
Performs the same substitution as String#sub in-place.
Returns str if a substitution was performed or nil if no substitution was performed.
Performs the substitutions of String#gsub in place, returning str, or nil if no substitutions were performed. If no block and no replacement is given, an enumerator is returned instead.
Processes str as for String#chop, returning str, or nil if str is the empty string. See also String#chomp!.
Modifies str in place as described for String#chomp, returning str, or nil if no modifications were made.
Returns a copy of str with all characters in the intersection of its arguments deleted. Uses the same rules for building the set of characters as String#count.
"hello".delete "l","lo" #=> "heo" "hello".delete "lo" #=> "he" "hello".delete "aeiou", "^e" #=> "hell" "hello".delete "ej-m" #=> "ho"
Builds a set of characters from the other_str parameter(s) using the procedure described for String#count. Returns a new string where runs of the same character that occur in this set are replaced by a single character. If no arguments are given, all runs of identical characters are replaced by a single character.
"yellow moon".squeeze #=> "yelow mon" " now is the".squeeze(" ") #=> " now is the" "putters shoot balls".squeeze("m-z") #=> "puters shot balls"
Each other_str parameter defines a set of characters to count. The intersection of these sets defines the characters to count in str. Any other_str that starts with a caret ^ is negated. The sequence c1-c2 means all characters between c1 and c2. The backslash character \ can be used to escape ^ or - and is otherwise ignored unless it appears at the end of a sequence or the end of a other_str.
a = "hello world" a.count "lo" #=> 5 a.count "lo", "o" #=> 2 a.count "hello", "^l" #=> 4 a.count "ej-m" #=> 4 "hello^world".count "\\^aeiou" #=> 4 "hello-world".count "a\\-eo" #=> 4 c = "hello world\\r\\n" c.count "\\" #=> 2 c.count "\\A" #=> 0 c.count "X-\\w" #=> 3
Performs a delete operation in place, returning str, or nil if str was not modified.
Squeezes str in place, returning either str, or nil if no changes were made.