[Ride v4 and v3] String functions

⚠️ This is the documentation for the Standard library version 4 and 3. We recommend to use version 6. Go to version 6

⚠️ Fixed an error in the implementation of string functions related to incorrect determination of UTF-8 character boundaries when splitting strings and searching for substrings in case of the strings contain special characters. The error could lead to invalid strings containing sequences that do not match any UTF-8 character. The fix is applied after activation of feature #16 “Ride V5, dApp-to-dApp invocations” regardless of the Standard library version.

Name	Description	Complexity
contains(String, String): Boolean	Checks whether the string contains substring	3
drop(String, Int): String	Drops the first n characters of a string	1 for Standard Library version 3 20 for Standard Library version 4
dropRight(String, Int): String	Drops the last n characters of a string	19 for Standard Library version 3 20 for Standard Library version 4
indexOf(String, String): Int|Unit	Returns the index of the first occurrence of a substring	20 for Standard Library version 3 3 for Standard Library version 4
indexOf(String, String, Int): Int|Unit	Returns the index of the first occurrence of a substring after a certain index	20 for Standard Library version 3 3 for Standard Library version 4
lastIndexOf(String, String): Int|Unit	Returns the index of the last occurrence of a substring	20 for Standard Library version 3 3 for Standard Library version 4
lastindexOf(String, String, Int): Int|Unit	Returns the index of the last occurrence of a substring before a certain index	20 for Standard Library version 3 3 for Standard Library version 4
makeString(List[String], String): String	Concatenates list strings adding a separator	30
size(String): Int	Returns the size of a string	1
split(String, String): List[String]	Splits a string delimited by a separator into a list of substrings	100 for Standard Library version 3 75 for Standard Library version 4
take(String, Int): String	Takes the first n characters from a string	1 for Standard Library version 3 20 for Standard Library version 4
takeRight(String, Int): String	Takes the last n characters from a string	19 for Standard Library version 3 20 for Standard Library version 4

contains(String, String): Boolean

Checks whether the string contains substring.

⚠️ The contains function is added in Standard library version 4.

contains(haystack: String, needle: String): Boolean

Parameters

Parameter	Description
haystack: String	String to search in
needle: String	String to search for

Examples

{-# STDLIB_VERSION 4 #-}
{-# CONTENT_TYPE DAPP #-}
{-# SCRIPT_TYPE ACCOUNT #-}
  
"hello".contains("hell") # Returns true
"hello".contains("world") # Returns false

drop(String, Int): String

Drops the first n characters of a string.

drop(xs: String, number: Int): String

Parameters

Parameter	Description
xs: String	The string
number: Int	The number n

Examples

drop("Apple", 0) # Returns "Apple"
drop("Apple", 1) # Returns "pple"
drop("Apple", 3) # Returns "le"
drop("Apple", 5) # Returns an empty string
drop("Apple", 15) # Returns an empty string

dropRight(String, Int): String

Drops the last n characters of a string.

dropRight(xs: String, number: Int): String

Parameters

Parameter	Description
xs: String	The string
number: Int	The number n

Examples

dropRight("Apple", 0) # Returns "Apple"
dropRight("Apple", 1) # Returns "Appl"
dropRight("Apple", 3) # Returns "Ap"
dropRight("Apple", 5) # Returns an empty string
dropRight("Apple", 15) # Returns an empty string

indexOf(String, String): Int|Unit

Returns the index of the first occurrence of a substring.

indexOf(str: String, substr: String): Int|Unit

Parameters

Parameter	Description
str: String	The string
substr: String	The substring

Examples

indexOf("Apple","ple") # Returns 2
indexOf("Apple","le")  # Returns 3
indexOf("Apple","e")   # Returns 4

indexOf(String, String, Int): Int|Unit

Returns the index of the first occurrence of a substring after a certain index.

indexOf(str: String, substr: String, offset: Int): Int|Unit

Parameters

Parameter	Description
str: String	The string
substr: String	The substring
offset: Int	The index

Examples

indexOf("Apple","ple", 1)   # Returns 2
indexOf("Apple","le", 2)    # Returns 3
indexOf("Apple","e", 3)     # Returns 4
indexOf("Apple","p", 0)     # Returns 1
indexOf("Apple","p", 2)     # Returns 2
indexOf("Apple","p", 3)     # Returns unit

lastIndexOf(String, String): Int|Unit

Returns the index of the last occurrence of a substring.

lastIndexOf(str: String, substr: String): Int|Unit

Parameters

Parameter	Description
str: String	The string
substr: String	The substring

Examples

lastIndexOf("Apple","pp") # Returns 1
lastIndexOf("Apple","p") # Returns 2
lastIndexOf("Apple","s") # Returns unit

lastIndexOf(String, String, Int): Int|Unit

Returns the index of the last occurrence of a substring before a certain index.

lastIndexOf(str: String, substr: String, offset: Int): Int|Unit

Parameters

Parameter	Description
str: String	The string
substr: String	The substring
offset: Int	The index

Examples

lastIndexOf("mamamama","ma",4) # Returns 4
lastIndexOf("mamamama","ma",3) # Returns 2

makeString(List[String], String): String

Concatenates list strings adding a separator.

⚠️ The makeString function is added in Standard library version 4.

makeString(arr: List[String], separator: String): String

Parameters

Parameter	Description
arr: List[String]	List of strings to concatenate
separator: String	Separator

Example

makeString(["Apple","Orange","Mango"], " & ") # Returns "Apple & Orange & Mango"

size(String): Int

Returns the size of a string.

size(xs: String): Int

Parameters

Parameter	Description
xs: String	The string

Examples

size("Ap") # Returns 2
size("Appl") # Returns 4
size("Apple") # Returns 5

split(String, String): List[String]

Splits a string delimited by a separator into a list of substrings.

split(str: String, separator: String): List[String]

Parameters

Parameter	Description
str: String	The string
separator: Int	The separator

Examples

split("A.p.p.l.e", ".") # Returns ["A", "p", "p", "l", "e"]
split("Apple", ".") # Returns ["Apple"]
split("Apple", "") # Returns ["A", "p", "p", "l", "e"]
split("Ap.ple", ".") # Returns ["Ap","ple"]

take(String, Int): String

Takes the first n characters from a string.

take(xs: String, number: Int): String

Parameters

Parameter	Description
xs: String	The string
number: Int	The number n

Examples

take("Apple", 0) # Returns an empty string
take("Apple", 1) # Returns "A"
take("Apple", 3) # Returns "App"
take("Apple", 5) # Returns "Apple"
take("Apple", 15) # Returns "Apple"
take("Apple", -10) # Returns an empty string

takeRight(String, Int): String

Takes the last n characters from a string.

takeRight(xs: String, number: Int): String

Parameters

Parameter	Description
xs: String	The string
number: Int	The number n

Examples

takeRight("Apple", 0) # Returns an empty string
takeRight("Apple", 1) # Returns "A"
takeRight("Apple", 3) # Returns "ple"
takeRight("Apple", 5) # Returns "Apple"
takeRight("Apple", 15) # Returns "Apple"