Std\String

String – string manipulation and conversion.

Provides utilities for searching, transforming, splitting, and converting strings. Iterator-returning functions (split, lines, chars) use O(1) memory per element.

Functions

length : String -> Int

Returns the length of the string in bytes.

import length from Std\String in
length "hello"   # => 5

isEmpty : String -> Bool

Returns true if the string has zero length.

import isEmpty from Std\String in
isEmpty ""      # => true
isEmpty "hi"    # => false

toUpperCase : String -> String

Convert all characters to uppercase.

import toUpperCase from Std\String in
toUpperCase "hello"   # => "HELLO"

toLowerCase : String -> String

Convert all characters to lowercase.

import toLowerCase from Std\String in
toLowerCase "HELLO"   # => "hello"

trim : String -> String

Remove leading and trailing whitespace.

import trim from Std\String in
trim "  hello  "   # => "hello"

indexOf : String -> String -> Int

Return the index of the first occurrence of needle, or -1 if not found.

import indexOf from Std\String in
indexOf "hello world" "world"   # => 6

contains : String -> String -> Bool

Returns true if str contains needle.

import contains from Std\String in
contains "hello world" "world"   # => true

startsWith : String -> String -> Bool

Returns true if str starts with prefix.

import startsWith from Std\String in
startsWith "hello" "hel"   # => true

endsWith : String -> String -> Bool

Returns true if str ends with suffix.

import endsWith from Std\String in
endsWith "hello.txt" ".txt"   # => true

substring : String -> Int -> Int -> String

Extract a substring from index start (inclusive) to end (exclusive).

import substring from Std\String in
substring "hello" 1 4   # => "ell"

replace : String -> String -> String -> String

Replace all occurrences of old with new.

import replace from Std\String in
replace "aabaa" "a" "x"   # => "xxbxx"

split : String -> String -> Iterator a

Split a string by a delimiter. Returns an Iterator String.

import split from Std\String in
let iter = split "a,b,c" "," in
# consume with iterator protocol

join : String -> [a] -> String

Join a sequence of strings with a separator.

import join from Std\String in
join ", " ["a", "b", "c"]   # => "a, b, c"

charAt : String -> Int -> Int

Returns the character code (Int) at the given index.

import charAt from Std\String in
charAt "ABC" 0   # => 65

padLeft : Int -> String -> String -> String

Pad str on the left with pad until it reaches width.

import padLeft from Std\String in
padLeft 5 "0" "42"   # => "00042"

padRight : Int -> String -> String -> String

Pad str on the right with pad until it reaches width.

import padRight from Std\String in
padRight 5 "." "hi"   # => "hi..."

reverse : String -> String

Reverse a string.

import reverse from Std\String in
reverse "hello"   # => "olleh"

repeat : Int -> String -> String

Repeat a string n times.

import repeat from Std\String in
repeat 3 "ab"   # => "ababab"

take : Int -> String -> String

Take the first n characters of a string.

import take from Std\String in
take 3 "hello"   # => "hel"

drop : Int -> String -> String

Drop the first n characters of a string.

import drop from Std\String in
drop 3 "hello"   # => "lo"

count : String -> String -> Int

Count the number of non-overlapping occurrences of needle in str.

import count from Std\String in
count "ababa" "ab"   # => 2

lines : String -> Iterator a

Split a string into lines. Returns an Iterator String.

import lines from Std\String in
let iter = lines "a\nb\nc" in
# consume with iterator protocol

unlines : [a] -> String

Join a sequence of strings with newline separators.

import unlines from Std\String in
unlines ["a", "b", "c"]   # => "a\nb\nc"

chars : String -> Iterator a

Returns an Iterator over individual characters of the string.

import chars from Std\String in
let iter = chars "hello" in
# consume with iterator protocol

fromChars : [a] -> String

Build a string from a sequence of character codes.

import fromChars from Std\String in
fromChars [72, 105]   # => "Hi"

toInt : String -> Int

Parse a string as an integer.

import toInt from Std\String in
toInt "42"   # => 42

toFloat : String -> Float

Parse a string as a float.

import toFloat from Std\String in
toFloat "3.14"   # => 3.14