string

string

string provides constants and functions to manipulate strings, it's intended to be a drop-in subset of Python's string module for Starlark.

Constants

• ascii_lowercase: A string containing all the characters that are considered lowercase letters.
• ascii_uppercase: A string containing all the characters that are considered uppercase letters.
• ascii_letters: A string containing all the characters that are considered letters.
• digits: A string containing all characters considered decimal digits: 0123456789.
• hexdigits: A string containing all characters considered hexadecimal digits: 0123456789abcdefABCDEF.
• octdigits: A string containing all characters considered octal digits: 01234567.
• punctuation: A string containing all characters which are considered punctuation characters.
• whitespace: A string containing all characters that are considered whitespace.
• printable: A string containing all characters that are considered printable. This is a combination of digits, ascii_letters, punctuation, and whitespace

Functions

length(obj) int

Returns the length of the object; for string, it returns the number of Unicode code points, instead of bytes like len().

Parameters

name	type	description
obj	string	The object whose length is to be calculated

Examples

String

Calculate the length of a CJK string.

load("string", "length")
s = "你好"
print(length(s), len(s))
# Output: 2 6

Misc

Calculate the length of a list, set and map.

load("string", "length")
print(length([1, 2, 3]), length(set([1, 2])), length({1: 2}))
# Output: 3 2 1

reverse(str) string

Returns the reversed string of the given value.

Parameters

name	type	description
str	string	A string that is to be reversed

Examples

Basic

Reverse a string.

load("string", "reverse")
s = "123我爱你"
print(reverse(s))
# Output: 你爱我321

index(s, sub) int

Returns the index of the first occurrence of the substring sub in s. If the substring is not found, an error is raised.

Parameters

name	type	description
s	string	The string to be searched
sub	string	The substring to search for

Examples

Basic

Find the first occurrence of a substring in a string.

load("string", "index")
s = "hello world"
print(index(s, "o"))
# Output: 4

rindex(s, sub) int

Returns the index of the last occurrence of the substring sub in s. If the substring is not found, an error is raised.

Parameters

name	type	description
s	string	The string to be searched
sub	string	The substring to search for

Examples

Basic

Find the last occurrence of a substring in a string.

load("string", "rindex")
s = "hello world"
print(rindex(s, "o"))
# Output: 7

find(s, sub) int

Returns the index of the first occurrence of the substring sub in s. If the substring is not found, returns -1.

Parameters

name	type	description
s	string	The string to be searched
sub	string	The substring to search for

Examples

Basic

Find the first occurrence of a substring in a string, returning -1 if not found.

load("string", "find")
s = "hello world"
print(find(s, "o"))
print(find(s, "x"))
# Output: 4
# Output: -1

rfind(s, sub) int

Returns the index of the last occurrence of the substring sub in s. If the substring is not found, returns -1.

Parameters

name	type	description
s	string	The string to be searched
sub	string	The substring to search for

Examples

Basic

Find the last occurrence of a substring in a string, returning -1 if not found.

load("string", "rfind")
s = "hello world"
print(rfind(s, "o"))
print(rfind(s, "x"))
# Output: 7
# Output: -1

substring(s, start, end) string

Returns a substring of s from index start to end (exclusive).

Parameters

name	type	description
s	string	The string to be sliced
start	int	The starting index for the substring
end	int	The ending index for the substring

Examples

Basic

Get a substring of a string.

load("string", "substring")
s = "hello world"
print(substring(s, 1, 5))
# Output: "ello"

Negative Indices

Get a substring of a string using negative indices.

load("string", "substring")
s = "hello world"
print(substring(s, -5, -1))
# Output: "worl"

codepoint(s, index) string

Returns the Unicode codepoint of the character at the given index in s.

Parameters

name	type	description
s	string	The string from which to get the codepoint
index	int	The index of the character

Examples

Basic

Get the Unicode codepoint of a character at a specific index.

load("string", "codepoint")
s = "hello world"
print(codepoint(s, 4))
# Output: "o"

escape(str) string

Converts the characters "&", "<", ">", '"' and "'" in string to their corresponding HTML entities.

Parameters

name	type	description
str	string	A string which is to be HTML escaped

Examples

Basic

Escape a string.

load("string", "escape")
s = "Hello<World>"
print(escape(s))
# Output: Hello&lt;World&gt;

unescape(str) string

Converts the HTML entities in a string back to their corresponding characters.

Parameters

name	type	description
str	string	A HTML escaped string

Examples

Basic

Unescape a string.

load("string", "unescape")
s = "You&Me"
print(unescape(s))
# Output: "You&Me"

quote(str) string

Returns a shell-escaped version of the string str. This returns a string that can safely be used as one token in a shell command line.

Parameters

name	type	description
str	string	A string which is to be quoted

Examples

Basic

Quote a string.

load("string", "quote")
s = "Hello World"
print(quote(s))
# Output: "Hello World"

unquote(str) string

Returns a shell-unescaped version of the string str. This returns a string that was used as one token in a shell command line.

Parameters

name	type	description
str	string	A string which is to be unquoted

Examples

Basic

Unquote a string.

load("string", "unquote")
s = '"Hello\tWorld"'
print(unquote(s))
World