strings

The strings module provides string utility functions that complement Starlark's built-in string methods. Functions that duplicate Starlark builtins have been removed in favor of the native equivalents.

Functions

Function	Returns	Description
strings.ljust(s, width, fillchar=" ")	string	Left-justify s in a field of width, padding with fillchar
strings.rjust(s, width, fillchar=" ")	string	Right-justify s in a field of width, padding with fillchar
strings.center(s, width, fillchar=" ")	string	Center s in a field of width, padding with fillchar
strings.cut(s, sep)	tuple	Cut s at the first occurrence of sep, returning (before, after, found)
strings.equal(s, t)	bool	Case-insensitive string equality
strings.has_any(s, chars)	bool	Return True if s contains any character in chars
strings.quote(s)	string	Add quoting to s (Go-style quoted string)
strings.unquote(s)	string	Remove quoting from s

Use Starlark Builtins Instead

The following operations are handled directly by Starlark's built-in string methods. There is no need to use a module function:

Operation	Starlark Builtin
Contains	sub in s
Upper/Lower	s.upper() / s.lower()
Split	s.split(sep)
Join	sep.join(parts)
Replace	s.replace(old, new)
Strip	s.strip() / s.lstrip() / s.rstrip()
Starts/Ends with	s.startswith(prefix) / s.endswith(suffix)

Examples

Padding and alignment

name = "kite"
print(strings.ljust(name, 20))        # "kite                "
print(strings.rjust(name, 20))        # "                kite"
print(strings.center(name, 20, "-"))   # "--------kite--------"

Cutting a string

before, after, found = strings.cut("host:8080", ":")
print(before)  # "host"
print(after)   # "8080"
print(found)   # True

_, _, found = strings.cut("no-colon", ":")
print(found)  # False

Case-insensitive comparison

if strings.equal("Hello", "hello"):
    print("match!")  # prints

Character membership

if strings.has_any("hello!", "!@#$"):
    print("has special characters")

Quoting

quoted = strings.quote('hello "world"')
print(quoted)  # "hello \"world\""

original = strings.unquote(quoted)
print(original)  # hello "world"

Note: All strings functions that can fail support try_ variants that return a Result instead of raising an error.