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String - Core helpers

This page lists all string operations available in the core package of lo.

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  • RandomString​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Returns a random string of the specified length from the given charset.

    str := lo.RandomString(5, lo.LettersCharset)
    // e.g., "eIGbt"
    Similar:
    camelcasecapitalizechunkstringkebabcasepascalcasesnakecasesubstringwords
    Prototype:
    func RandomString(size int, charset []rune) string

  • Substring​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Returns a substring starting at the given offset with the specified length. Supports negative offsets; out-of-bounds are clamped. Operates on Unicode runes (characters) and is optimized for zero allocations.

    // Basic usage
    result := lo.Substring("hello", 2, 3)
    // result: "llo"

    // Negative offset - counts from end
    result = lo.Substring("hello", -4, 3)
    // result: "ell"

    // Length longer than string - clamped to available characters
    result = lo.Substring("hello", 1, 10)
    // result: "ello" (only 4 characters available from position 1)

    // Zero length - returns empty string
    result = lo.Substring("hello", 1, 0)
    // result: ""

    // Offset beyond string length - returns empty string
    result = lo.Substring("hello", 10, 3)
    // result: ""

    // With Unicode strings (rune-aware)
    result = lo.Substring("héllo", 1, 3)
    // result: "él"

    // Negative offset with negative values clamped
    result = lo.Substring("hello", -10, 3)
    // result: "hel" (offset clamped to 0)
    Similar:
    chunkstringellipsisreplacereplaceallrunelengthwords
    Prototype:
    func Substring[T ~string](str T, offset int, length uint) T

  • ChunkString​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Splits a string into chunks of the given size. The last chunk may be shorter. Returns [""] for empty input.

    lo.ChunkString("1234567", 2)
    // []string{"12", "34", "56", "7"}
    Similar:
    chunkrunelengthsplitsubstringwords
    Prototype:
    func ChunkString[T ~string](str T, size int) []T

  • RuneLength​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Returns the number of runes (Unicode code points) in a string.

    lo.RuneLength("hellô")
    // 5
    Similar:
    capitalizechunkstringellipsissubstringwords
    Prototype:
    func RuneLength(str string) int

  • PascalCase​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Converts a string to PascalCase.

    lo.PascalCase("hello_world")
    // "HelloWorld"

    PascalCaseWithLanguage uses a locale-aware title caser. This matters for languages such as Turkish, where the uppercase of i is İ (dotted I), not I.

    lo.PascalCaseWithLanguage("istanbul_city", language.Turkish)
    // "İstanbulCity"
    Variant:
    pascalcasewithlanguage
    Similar:
    camelcasecapitalizekebabcasesnakecasewords
    Prototypes:
    func PascalCase(str string) string
    func PascalCaseWithLanguage(str string, tag language.Tag) string

  • CamelCase​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Converts a string to camelCase.

    lo.CamelCase("hello_world")
    // "helloWorld"

    CamelCaseWithLanguage uses locale-aware casing. The first word is fully lowercased, subsequent words are title-cased, both according to the given language tag.

    lo.CamelCaseWithLanguage("ISTANBUL_CITY", language.Turkish)
    // "ıstanbulCıty"  (capital I → ı, title I → İ in Turkish)
    Variant:
    camelcasewithlanguage
    Similar:
    capitalizekebabcasepascalcasesnakecasewords
    Prototypes:
    func CamelCase(str string) string
    func CamelCaseWithLanguage(str string, tag language.Tag) string

  • KebabCase​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Converts a string to kebab-case.

    lo.KebabCase("helloWorld")
    // "hello-world"

    KebabCaseWithLanguage uses a locale-aware lowercase caser instead of strings.ToLower. This matters for languages such as Turkish, where capital I lowercases to ı (dotless i, U+0131), not i.

    lo.KebabCaseWithLanguage("ISTANBUL_CITY", language.Turkish)
    // "ıstanbul-cıty"

    lo.KebabCaseWithLanguage("ISTANBUL_CITY", language.English)
    // "istanbul-city"
    Variant:
    kebabcasewithlanguage
    Similar:
    camelcasecapitalizepascalcasesnakecasewords
    Prototypes:
    func KebabCase(str string) string
    func KebabCaseWithLanguage(str string, tag language.Tag) string

  • SnakeCase​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Converts a string to snake_case.

    lo.SnakeCase("HelloWorld")
    // "hello_world"

    SnakeCaseWithLanguage uses a locale-aware lowercase caser instead of strings.ToLower. This matters for languages such as Turkish, where capital I lowercases to ı (dotless i, U+0131), not i.

    lo.SnakeCaseWithLanguage("ISTANBUL_CITY", language.Turkish)
    // "ıstanbul_cıty"

    lo.SnakeCaseWithLanguage("ISTANBUL_CITY", language.English)
    // "istanbul_city"
    Variant:
    snakecasewithlanguage
    Similar:
    camelcasecapitalizekebabcasepascalcasewords
    Prototypes:
    func SnakeCase(str string) string
    func SnakeCaseWithLanguage(str string, tag language.Tag) string

  • Words​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Splits a string into a slice of its words, separating letters and digits and removing non-alphanumeric separators.

    lo.Words("helloWorld")
    // []string{"hello", "world"}
    Similar:
    camelcasecapitalizechunkstringkebabcasepascalcasesnakecasesubstring
    Prototype:
    func Words(str string) []string

  • Capitalize​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Converts the first character to uppercase and the remaining to lowercase.

    lo.Capitalize("heLLO")
    // "Hello"

    CapitalizeWithLanguage uses a locale-aware title caser. This matters for languages such as Turkish, where the uppercase of i is İ (dotted I), not I.

    lo.CapitalizeWithLanguage("istanbul", language.Turkish)
    // "İstanbul"

    lo.CapitalizeWithLanguage("istanbul", language.English)
    // "Istanbul"
    Variant:
    capitalizewithlanguage
    Similar:
    camelcasekebabcasepascalcaserunelengthsnakecasewords
    Prototypes:
    func Capitalize(str string) string
    func CapitalizeWithLanguage(str string, tag language.Tag) string

  • Ellipsis​

    stringcore
    🧩 Source📚 GoDoc🎮 Try on Go Playground

    Trims and truncates a string to the specified length in runes (Unicode code points) and appends an ellipsis if truncated. Multi-byte characters such as emoji or CJK ideographs are never split in the middle.

    lo.Ellipsis("  Lorem Ipsum  ", 5)
    // "Lo..."

    str = lo.Ellipsis("Lorem Ipsum", 100)
    // "Lorem Ipsum"

    str = lo.Ellipsis("Lorem Ipsum", 3)
    // "..."

    str = lo.Ellipsis("hello 世界! 你好", 8)
    // "hello..."

    str = lo.Ellipsis("🏠🐶🐱🌟", 4)
    // "🏠🐶🐱🌟"
    Similar:
    capitalizerunelengthsubstringtrim
    Prototype:
    func Ellipsis(str string, length int) string