Ruby String Methods - ashish9342/FreeCodeCamp GitHub Wiki
Ruby has many built in methods to work with strings. Strings in Ruby by default are mutable and can be changed in place or a new string can be returned from a method.
- The
.length
property returns the number of characters in a string including white-space.
"Hello".length
# returns: 5
"Hello World!".length
# returns: 12
- The
.count
method counts how many times a specific character(s) is found in a string. - This method is case-sensitive.
"HELLO".count('L')
# returns: 2
"HELLO WORLD!".count('LO')
# returns: 1
- The
.insert
method inserts a string into another string before a given index.
"Hello".insert(3, "hi5")
# returns:
Helhi5lo
# "hi5" is inserted into the string right before the second 'l' which is at index 3
- The
.upcase
method transforms all letters in a string to uppercase.
"Hello".upcase
# returns:
HELLO
- The
.downcase
method transforms all letters in a string to lowercase.
"Hello".downcase
# returns:
hello
- The
.capitalize
method make the first letter in a string uppercase and the rest of the string lowercase.
"HELLO".capitalize
# returns:
Hello
"HELLO, HOW ARE YOU?".capitalize
# returns:
Hello, how are you?
Note that the first letter is only capitilized if it is at the beginning of the string.
"-HELLO".capitalize
"1HELLO".capitalize
# returns:
-hello
1hello
- The
.reverse
method reverses the order of the characters in a string.
"Hello World!".reverse
# returns:
"!dlroW olleH"
- The
.split
takes a strings and splits it into an array, then returns the array. - The default method splits the string based on whitespace, unless a different separator is provided (see second example).
"Hello, how are you?".split
# returns:
["Hello,", "how", "are", "you?"]
"H-e-l-l-o".split('-')
# returns:
["H", "e", "l", "l", "o"]
- The
.chop
method removes the last character of the string. - A new string is returned, unless you use the
.chop!
method which mutates the original string.
"Name".chop
# returns:
Nam
name = "Batman"
name.chop
name == "Batma" # returns false
name = "Batman"
name.chop!
name == "Batma" # returns true
- The
.strip
method removes the leading and trailing whitespace on strings, including tabs, newlines, and carriage returns (\t
,\n
,\r
).
" Hello ".strip
# returns:
Hello
- The
.chomp
method removes the last character in a string, only if it’s a carriage return or newline (\r
,\n
). - This method is commonly used with the
gets
command to remove returns from user input.
"hello\r".chomp
# returns:
hello
"hello\t".chomp
# returns:
hello\t #because tabs and other whitespace remain intact when using `chomp`
- The
.to_i
method converts a string to an integer.
"15".to_i
# returns:
15 #integer
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