# String functions

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") # Возвращает true
"hello".contains("world") # Возвращает 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 3
indexOf("Apple","le") # Returns 4
indexOf("Apple","e") # Returns 5

# 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

# 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

# Параметры

# Parameters

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

# Пример

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"