本篇文章說明兩個 package 的部分函式，strings package 和 strconv package

strings package

Official Document

ToUpper

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func ToUpper(s string) string

strings.ToUpper("Gopher") // GOPHER

ToLower

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func ToLower(s string) string

strings.ToLower("Gopher") // gopher

Replace

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func Replace(s, old, new string, n int) string

strings.Replace("oink oink oink", "k", "ky", 2)      // oinky oinky oink
strings.Replace("oink oink oink", "oink", "moo", -1) // moo moo moo

Split

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func Split(s, sep string) []string

strings.Split("a,b,c", ",")                        // ["a" "b" "c"]
strings.Split("a man a plan a canal panama", "a ") // ["" "man " "plan " "canal panama"]
strings.Split(" xyz ", "")                         // [" " "x" "y" "z" " "]
strings.Split("", "Bernardo O'Higgins")            // [""]a

strconv package

Official Document

ParseInt and Atoi

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func ParseInt(s string, base int, bitSize int) (i int64, err error)

if s, err := strconv.ParseInt("16", 10, 32); err == nil {
    fmt.Printf("%T, %v\n", s, s) // int64, 16
}

Atoi is equivalent to ParseInt(s, 10, 0), converted to type int.

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func Atoi(s string) (int, error)

s, err := strconv.Atoi("10"); // 10

ParseFloat

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func ParseFloat(s string, bitSize int) (float64, error)

if s, err := strconv.ParseFloat("3.1415926535", 32); err == nil {
    fmt.Printf("%T, %v\n", s, s) // float64, 3.1415927410125732
}

if s, err := strconv.ParseFloat(v, 64); err == nil {
    fmt.Printf("%T, %v\n", s, s) // float64, 3.1415926535
}

ParseBool

It accepts 1, t, T, TRUE, true, True, 0, f, F, FALSE, false, False. 

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func ParseBool(str string) (bool, error)

s, err := strconv.ParseBool("true"); // true

Itoa

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func Itoa(i int) string

s := strconv.Itoa(10) // "10"

Contains

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func Contains(s, substr string) bool

strings.Contains("seafood", "foo") // true
strings.Contains("seafood", "bar") // false