Class: String

A string is a sequence of UTF-8 characters enclosed betweend double quotes.

Up to now no special characters have been introduced (like ‘\n’ or similar) nor particular string options like string interpolation, but they’re planned to be implemented in future.

Users must be careful with method aliases: this type has methods which modify the content of a sring, and others which return a new one. The first ones usually end with !, but there are some exceptions like String#[]=

Defined in:

String.cr

Index:

str * integer -> new_string

Performs a multiplication between a string and a number

bark   := "Bark"
bark_3 := bark * 3 #=> "BarkBarkBark"

see definition

str + other_str -> new_str

Adds two strings. This method can be invoked in two ways:

foo    := "Foo"
bar    := "Bar"
foobar := foo + bar #=> "FooBar"

see definition

str == other -> boolean

Compares two strings or a string with another object

bar := "Bar"
foo := "Foo"
bar == bar #=> true
bar == foo #=> false
bar == 2   #=> false

see definition

str[index] -> string or null

str[range] -> string

Access the string characters at the given index

str := "A quite long string"
str[0]    #=> "A"
str[8]    #=> "l"
str[2..6] #=> "quite"

see definition

str[index] = string -> str

Sets a char or a set of chars in a specified index

a    := "Gun"
a[0] := "F"    #=> "Fun"
a[2] := "fair" #=> "Funfair"
a[8] := "!"    #=> Raises an error

see definition

chars() -> array

Returns an array containing each char of the string

"abc".chars() #=> ["a","b","c"]

see definition

clone() -> new_str

Clones a string

a := "Foo"
b := a         # b and a are pointing to the same object
# Now b and c are going to point to two different objects
c := a.clone() #=> "Foo"

see definition

compact() -> new_str

Clones the string and deletes the spaces on this last one

"Compacting This String".compact() #=> "CompactingThisString"

see definition

compact!() -> str

Deletes the spaces of str

"Compacting This String".compact!() #=> "CompactingThisString"

see definition

concat(str1,str2,str3…) -> str

Concatenates other strings at the given one

a := "1"
a.concat("2")     #=> "12"
a.concat("3","4") #=> "1234"

see definition

each(&block) -> str

Iterates over each char of the string

"abcd".each_char() { (chr)
print "Char: ",chr
printl
}

#=> Char: a
#=> Char: b
#=> Char: c
#=> Char: d

see definition

gsub(pattern,replacement) -> new_str

Returns a new string where every occurrence of pattern replaced with the content in replacement

"comfort".gsub("o","*")    #=> c*mf*rt
"comfort".gsub("com","ef") #=> effort

see definition

hash() -> integer

Return string hash based on length and content

see definition

include?(string) -> boolean

Checks if a substring is contained in another one. It works making a call like this:

str := "A cat on the roof"
cat := "Cat"
str.include(cat)   #=> true
str.include("bed") #=> false

see definition

init(string) -> new_string

Initializes a new string through the keyword ‘new’ or just assigning it. This is the ‘init’ method of the class

str := "Foo"             #=> Foo
str := new String("Foo") #=> Foo

see definition

insert(index,string) -> str

Inserts a second string in the current one

a := "0234"
a.insert(1,"1") #=> "01234"
a.insert(5,"5") #=> "012345"
a.insert(7,"6") #=> Raises an error

see definition

lowcase() -> new_string

Performs the downcase on the whole string without overwriting the original one

"FOO.lowcase() #=> "foo"

see definition

lowcase!() -> str

Performs the downcase on the whole string overwriting the original one

"FOO.lowcase!() #=> "foo"

see definition

size() -> integer

length() -> integer [alias]

Returns the string size

a := "Hello, world"
a.size() #=> 12

see definition

split(delimiter := “ “) -> array

Splits a string according to a specific delimiter, returning an array. If delimiter is not specified, a white space will be used

a := "a,b,c,d"
a.split(",") #=> ["a","b","c","d"]

see definition

starts_with?(str_beg) -> boolean

Returns true if the beginning of str matches str_beg, false in all the other cases

"hola".starts_with? ("h")  #=> true
"hola".statrs_with? ("ho") #=> true

see definition

to_f() -> float

Converts a string into a float number

"12".to_f()     #=> 12.0
"12.24".to_f()  #=> 12.24
"12.ab".to_f()  #=> 12.0
"abcd".to_f()   #=> 0.0

see definition

to_i() -> integer

Converts a string into an integer number. Warning: no overflow is checked yet

"12".to_i()   #=> 12
"12x".to_i()  #=> 12
"abcd".to_i() #=> 0

see definition

to_sym() -> symbol

Converts str into a symbol

"foo".to_sym() #=> :foo
"32".to_sym()  #=> :"32"

see definition

upcase() -> new_string

Performs the upcase on the whole string without overwriting the original one

"foo".upcase() #=> "FOO"

see definition

upcase!() -> str

Performs the upcase on the whole string overwriting the original one

"foo".upcase!() #=> "FOO"

see definition