Character string

• string is a data type, not a reference or pointer type
• string is a read-only byte slice. The len function can get all the bytes
• The byte array of string can hold any data

func TestString(t *testing.T) {
    var s string
    t.Log(s) //Initialize to default zero value ''
    s = "hello"
    t.Log(len(s))
    //s[1] = '3' //string is immutable byte slice
    s = "\xE4\xB8\xA5"
    t.Log(s)
    t.Log(len(s))
    //s = "medium"
    //t.Log(len(s))
    //c := []rune(s)
    //t.Log("rune size:", unsafe.Sizeof(c[0]))
    //t.Logf("Unicode% X in, C [0])
    //t.Logf("utf8% X", s)
}

output

=== RUN   TestString
--- PASS: TestString (0.00s)
    string_test.go:9: 
    string_test.go:11: 5
    string_test.go:14: strict
    string_test.go:15: 3
PASS

Process finished with exit code 0

Unicode UTF8

• Unicode is a character set (code point)
• UTF8 is a storage implementation of unicode (rules for converting to byte sequences)

Coding and storage

Common string functions

• string package ( https://golang.org/pkg/strings/)
• strconv package( https://golang.org/pkg/strconv/)

func TestStringToRune(t *testing.T) {
    s := "The People's Republic of China"
    for _, c := range s {
        t.Logf("%[1]c %[1]d", c)
    }
}

output

=== RUN   TestStringToRune
--- PASS: TestStringToRune (0.00s)
    string_test.go:28: Middle 20013
    string_test.go:28: Hua 21326
    string_test.go:28: Man 20154
    string_test.go:28: Min 27665
    string_test.go:28: A total of 20849
    string_test.go:28: And 21644
    string_test.go:28: 22269 China
PASS

Process finished with exit code 0

Transformation

func TestConv(t *testing.T) {
    s := strconv.Itoa(10)
    t.Log("str:" + s)
    if i,err:=strconv.Atoi("10");err==nil{
        t.Log(10+ i)
    }

}

=== RUN   TestConv
--- PASS: TestConv (0.00s)
    string_fun_test.go:20: str:10
    string_fun_test.go:22: 20
PASS

Process finished with exit code 0

For example code, please visit: https://github.com/wenjianzhang/golearning