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String Methods

Strings in Risor have a rich set of built-in methods for searching, splitting, transforming, and inspecting text. All string methods are non-mutating. They return new strings rather than modifying the original.

Method Reference

Method	Description
`compare(other)`	Compare to another string, returns -1, 0, or 1
`contains(substr)`	True if the string contains `substr`
`split(sep)`	Split into a list on the given separator
`to_upper()`	Convert to uppercase
`to_lower()`	Convert to lowercase
`trim_space()`	Remove leading and trailing whitespace
`trim(chars)`	Remove leading and trailing characters
`trim_prefix(prefix)`	Remove prefix if present, returns string unchanged if not
`trim_suffix(suffix)`	Remove suffix if present, returns string unchanged if not
`has_prefix(prefix)`	True if the string starts with `prefix`
`has_suffix(suffix)`	True if the string ends with `suffix`
`index(substr)`	Index of first occurrence, or -1
`last_index(substr)`	Index of last occurrence, or -1
`replace_all(old, new)`	Replace all occurrences of `old` with `new`
`join(list)`	Join list elements using the string as separator
`count(substr)`	Count non-overlapping occurrences of `substr`
`repeat(n)`	Repeat the string `n` times
`fields()`	Split on whitespace into a list of words

Searching

compare

Compare two strings lexicographically. Returns -1 if the receiver is less than the other string, 0 if they are equal, or 1 if the receiver is greater.

"apple".compare("banana")    // -1
"banana".compare("banana")   // 0
"cherry".compare("banana")   // 1

contains

Check whether a string contains a substring.

"hello world".contains("world")   // true
"hello world".contains("xyz")     // false

has_prefix

Check whether a string starts with a given prefix.

"hello".has_prefix("he")    // true
"hello".has_prefix("lo")    // false

has_suffix

Check whether a string ends with a given suffix.

"hello".has_suffix("lo")    // true
"hello".has_suffix("he")    // false

index

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

"hello".index("ll")    // 2
"hello".index("xyz")   // -1

last_index

Return the index of the last occurrence of a substring, or -1 if not found.

"hello hello".last_index("hello")   // 6
"hello".last_index("xyz")           // -1

count

Count the number of non-overlapping occurrences of a substring.

"hello hello".count("hello")   // 2
"aaa".count("aa")              // 1

Splitting and Joining

split

Split a string into a list of substrings on a separator.

"hello world".split(" ")      // ["hello", "world"]
"a,b,c".split(",")            // ["a", "b", "c"]

fields

Split a string on whitespace, returning a list of non-empty words. This handles multiple spaces, tabs, and newlines.

"hello world".fields()         // ["hello", "world"]
"  foo   bar  baz  ".fields()  // ["foo", "bar", "baz"]

join

Join a list of strings using the receiver as the separator.

", ".join(["a", "b", "c"])    // "a, b, c"
"-".join(["2024", "01", "15"]) // "2024-01-15"

Note that the separator is the receiver and the list is the argument.

Transforming

to_upper

Convert a string to uppercase.

"hello".to_upper()    // "HELLO"

to_lower

Convert a string to lowercase.

"HELLO".to_lower()    // "hello"

replace_all

Replace all occurrences of a substring with another string.

"hello".replace_all("l", "r")         // "herro"
"foo bar foo".replace_all("foo", "baz") // "baz bar baz"

repeat

Repeat a string a given number of times.

"abc".repeat(3)    // "abcabcabc"
"ha".repeat(0)     // ""

Trimming

trim_space

Remove leading and trailing whitespace (spaces, tabs, newlines).

"  hello  ".trim_space()    // "hello"
"\thello\n".trim_space()    // "hello"

trim

Remove leading and trailing characters from a set.

"  hello  ".trim(" ")       // "hello"
"xxhelloxx".trim("x")       // "hello"

trim_prefix

Remove a prefix from the string if present. If the string does not start with the prefix, it is returned unchanged.

"hello world".trim_prefix("hello ")   // "world"
"hello world".trim_prefix("xyz")      // "hello world"

trim_suffix

Remove a suffix from the string if present. If the string does not end with the suffix, it is returned unchanged.

"hello world".trim_suffix(" world")   // "hello"
"hello world".trim_suffix("xyz")      // "hello world"

Utility Functions

List Methods

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