参考https://studygolang.com/pkgdoc
导入方式：
import "strings"
strings包实现了用于操作字符的简单函数。
常用的几个函数：
func Contains
func Contains(s, substr string) bool
判断字符串s是否包含子串substr。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Println(strings.Contains("seafood", "foo")) //true fmt.Println(strings.Contains("seafood", "bar")) //false fmt.Println(strings.Contains("seafood", "")) //true fmt.Println(strings.Contains("", "")) //true }
func Index
func Index(s, sep string) int
子串sep在字符串s中第一次出现的位置，不存在则返回-1。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Println(strings.Index("chicken", "ken")) //4 fmt.Println(strings.Index("chicken", "dmr")) //-1 }
func Join
func Join(a []string, sep string) string
将一系列字符串连接为一个字符串，之间用sep来分隔。
举例：
package main import( "fmt" "strings" ) func main() { s := []string{"foo", "bar", "baz"} fmt.Println(strings.Join(s, ", "))//foo, bar, baz }
func Repeat
func Repeat(s string, count int) string
返回count个s串联的字符串。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Println("ba" + strings.Repeat("na", 2)) //banana }
func Replace
func Replace(s, old, new string, n int) string
返回将s中前n个不重叠old子串都替换为new的新字符串，如果n<0会替换所有old子串。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Println(strings.Replace("oink oink oink", "k", "ky", 2)) //oinky oinky oink fmt.Println(strings.Replace("oink oink oink", "oink", "moo", -1)) //moo moo moo }
func Split
func Split(s, sep string) []string
用去掉s中出现的sep的方式进行分割，会分割到结尾，并返回生成的所有片段组成的切片（每一个sep都会进行一次切割，即使两个sep相邻，也会进行两次切割）。如果sep为空字符，Split会将s切分成每一个unicode码值一个字符串。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Printf("%q ", strings.Split("a,b,c", ",")) //["a" "b" "c"] fmt.Printf("%q ", strings.Split("a man a plan a canal panama", "a ")) //["" "man " "plan " "canal panama"] fmt.Printf("%q ", strings.Split(" xyz ", "")) //[" " "x" "y" "z" " "] fmt.Printf("%q ", strings.Split("", "Bernardo O'Higgins")) //[""] }
func Trim
func Trim(s string, cutset string) string
返回将s前后端所有cutset包含的utf-8码值都去掉的字符串。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Printf("[%q] ", strings.Trim(" !!! Achtung! Achtung! !!! ", "! ")) //["Achtung! Achtung"] }
func Fields
func Fields(s string) []string
返回将字符串按照空白（unicode.IsSpace确定，可以是一到多个连续的空白字符）分割的多个字符串。如果字符串全部是空白或者是空字符串的话，会返回空切片。
举例：
package main import( "fmt" "strings" ) func main() { fmt.Printf("Fields are: %q ", strings.Fields(" foo bar baz ")) //Fields are: ["foo" "bar" "baz"] }
)type Reader
type Reader struct {
s string
i int64 // current reading index
prevRune int // index of previous rune; or < 0
Reader类型通过从一个字符串读取数据，实现了io.Reader、io.Seeker、io.ReaderAt、io.WriterTo、io.ByteScanner、io.RuneScanner接口。
实现源码：
1> func NewReader
func NewReader(s string) *Reader
NewReader创建一个从s读取数据的Reader。本函数类似bytes.NewBufferString，但是更有效率，且为只读的。
该初始化源码：
func NewReader(s string) *Reader { return &Reader{s, 0, -1} }
举例：
package main
import(
"fmt"
"io"
"strings"
"os"
)
func main() {
reader := strings.NewReader("test reader's usage")
buf := make([]byte, 4) //生成一个能够存放4 bytes数据的数组
for {//无限循环直至有错或数据读取完返回EOF
count, err := reader.Read(buf)//后面读取的内容会覆盖前面的buf的内容
if err != nil {
if err == io.EOF {
fmt.Println("EOF : ", count)
break
}
fmt.Println(err)
os.Exit(1)
}
fmt.Println(count, string(buf[:count]))
}
}
返回：
userdeMBP:src user$ go run test.go
4 test
4 rea
4 der'
4 s us
3 age
EOF : 0
2》func (*Reader) Len
func (r *Reader) Len() int
Len返回r包含的字符串还没有被读取的部分，即当前文件指针之后的内容
3》func (*Reader) Read
func (r *Reader) Read(b []byte) (n int, err error)
4》func (*Reader) ReadByte
func (r *Reader) ReadByte() (b byte, err error)
5》func (*Reader) UnreadByte
func (r *Reader) UnreadByte() error
6》func (*Reader) ReadRune
func (r *Reader) ReadRune() (ch rune, size int, err error)
7》func (*Reader) UnreadRune
func (r *Reader) UnreadRune() error
8》func (*Reader) ReadAt
func (r *Reader) ReadAt(b []byte, off int64) (n int, err error)
9》func (*Reader) WriteTo
func (r *Reader) WriteTo(w io.Writer) (n int64, err error)
WriteTo实现了io.WriterTo接口。
举例：
package main
import(
"fmt"
"strings"
"log"
"os"
)
func main() {
fmt.Println("1 - test Read")
reader := strings.NewReader("test strings's NewReader() and the usage of its function
")
len := reader.Len()
fmt.Printf("1 before - the length of the part have not beed read : %d
", len)
data := make([]byte, 8)
number, err := reader.Read(data)
if err != nil {
log.Fatal(err)
}
len = reader.Len()
fmt.Printf("1 after - the length of the part have not beed read : %d
", len)
fmt.Println(string(data[:number]))
fmt.Println("2 - test ReadByte")
for i := 0; i < 3; i++ {
readbyte, err := reader.ReadByte()//从当前文件指针向后读取一个byte的内容
if err != nil {
log.Fatal(err)
}
fmt.Print(readbyte, " ")
}
fmt.Println()
len = reader.Len()
fmt.Printf("2 after - the length of the part have not beed read : %d
", len)
fmt.Println("3 - test UnreadByte") //就相当于撤销之前的一次ReadByte()操作，文件指针向前移一位
err = reader.UnreadByte()
if err != nil {
log.Fatal(err)
}
len = reader.Len()
fmt.Printf("3 after - the length of the part have not beed read : %d
", len)
fmt.Println("4 - test ReadAt")
number1, err := reader.ReadAt(data, 11)
if err != nil {
log.Fatal(err)
}
len = reader.Len()
fmt.Printf("4 after - the length of the part have not beed read : %d
", len)
fmt.Println(string(data[:number1]))
fmt.Println("5 - test ReadRune")
for i := 0; i < 3; i++ {
readrune, _, err := reader.ReadRune()//从当前文件指针向后读取一个rune的内容
if err != nil {
log.Fatal(err)
}
fmt.Print(readrune, " ")
// fmt.Print(readrune)
}
fmt.Println()
len = reader.Len()
fmt.Printf("5 after - the length of the part have not beed read : %d
", len)
fmt.Println("6 - test UnreadRune")
err = reader.UnreadRune() //就相当于撤销之前的一次ReadByte()操作，文件指针向前移一位
if err != nil {
log.Fatal(err)
}
len = reader.Len()
fmt.Printf("6 after - the length of the part have not beed read : %d
", len)
fmt.Println("test WriterTo")
number3, err := reader.WriteTo(os.Stdout)//从当前指针开始将文件内容输出到os.Stdout，即标准输出中
if err != nil {
log.Fatal(err)
}
fmt.Println(number3)
}
返回：
userdeMBP:src user$ go run test.go
1 - test Read
1 before - the length of the part have not beed read : 57
1 after - the length of the part have not beed read : 49
test str
2 - test ReadByte
105 110 103 //即ing
2 after - the length of the part have not beed read : 46
3 - test UnreadByte
3 after - the length of the part have not beed read : 47
4 - test ReadAt
4 after - the length of the part have not beed read : 47
s's NewR
5 - test ReadRune
103 115 39 //即gs'
5 after - the length of the part have not beed read : 44
6 - test UnreadRune
6 after - the length of the part have not beed read : 45
test WriterTo
's NewReader() and the usage of its function
45
未完待续