mirror of
https://github.com/unknwon/the-way-to-go_ZH_CN.git
synced 2025-08-11 16:15:55 +08:00
精校：4.7
This commit is contained in:
Unknwon
@@ -91,7 +91,7 @@ F || F -> false
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### 4.5.2.1 整型 int 和浮点型 float
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Go 语言支持整型和浮点型数字，并且原生支持复数，其中位的运算采用补码（二的补码，详情参见：[http://en.wikipedia.org/wiki/Two's_complement](http://en.wikipedia.org/wiki/Two's_complement)）。
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Go 语言支持整型和浮点型数字，并且原生支持复数，其中位的运算采用补码（详情参见 [二的补码](http://en.wikipedia.org/wiki/Two's_complement) 页面）。
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Go 也有基于架构的类型，例如：int、uint 和 uintptr。
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324
eBook/04.7.md
324
eBook/04.7.md
@@ -6,26 +6,32 @@
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`HasPrefix` 判断字符串 `s` 是否以 `prefix` 开头：
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strings.HasPrefix(s, prefix string) bool
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```go
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strings.HasPrefix(s, prefix string) bool
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```
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`HasSuffix` 判断字符串 `s` 是否以 `suffix` 结尾：
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strings.HasSuffix(s, suffix string) bool
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```go
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strings.HasSuffix(s, suffix string) bool
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```
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Example 4.13 [presuffix.go](examples/chapter_4/presuffix.go)
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示例 4.13 [presuffix.go](examples/chapter_4/presuffix.go)
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package main
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```go
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package main
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import (
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"fmt"
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"strings"
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)
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import (
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"fmt"
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"strings"
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)
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func main() {
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var str string = "This is an example of a string"
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fmt.Printf("T/F? Does the string \"%s\" have prefix %s? ", str, "Th")
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fmt.Printf("%t\n", strings.HasPrefix(str, "Th"))
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}
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func main() {
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var str string = "This is an example of a string"
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fmt.Printf("T/F? Does the string \"%s\" have prefix %s? ", str, "Th")
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fmt.Printf("%t\n", strings.HasPrefix(str, "Th"))
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}
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```
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输出：
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@@ -43,39 +49,47 @@ Example 4.13 [presuffix.go](examples/chapter_4/presuffix.go)
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`Index` 返回字符串 `str` 在字符串 `s` 中的索引（`str` 的第一个字符的索引），-1 表示字符串 `s` 不包含字符串 `str`：
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strings.Index(s, str string) int
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```go
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strings.Index(s, str string) int
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```
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`LastIndex` 返回字符串 `str` 在字符串 `s` 中最后出现位置的索引（`str` 的第一个字符的索引），-1 表示字符串 `s` 不包含字符串 `str`：
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strings.LastIndex(s, str string) int
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```go
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strings.LastIndex(s, str string) int
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```
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如果 `ch` 是非 ASCII 编码的字符，建议使用以下函数来对字符进行定位：
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strings.IndexRune(s string, ch int) int
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```go
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strings.IndexRune(s string, ch int) int
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```
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Example 4.14 [index_in_string.go](examples/chapter_4/index_in_string.go)
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示例 4.14 [index_in_string.go](examples/chapter_4/index_in_string.go)
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var str string = "Hi, I'm Marc, Hi."
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fmt.Printf("The position of \"Marc\" is: ")
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fmt.Printf("%d\n", strings.Index(str, "Marc"))
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fmt.Printf("The position of the first instance of \"Hi\" is: ")
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fmt.Printf("%d\n", strings.Index(str, "Hi"))
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fmt.Printf("The position of the last instance of \"Hi\" is: ")
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fmt.Printf("%d\n", strings.LastIndex(str, "Hi"))
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fmt.Printf("The position of \"Burger\" is: ")
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fmt.Printf("%d\n", strings.Index(str, "Burger"))
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}
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```go
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var str string = "Hi, I'm Marc, Hi."
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fmt.Printf("The position of \"Marc\" is: ")
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fmt.Printf("%d\n", strings.Index(str, "Marc"))
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fmt.Printf("The position of the first instance of \"Hi\" is: ")
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fmt.Printf("%d\n", strings.Index(str, "Hi"))
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fmt.Printf("The position of the last instance of \"Hi\" is: ")
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fmt.Printf("%d\n", strings.LastIndex(str, "Hi"))
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fmt.Printf("The position of \"Burger\" is: ")
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fmt.Printf("%d\n", strings.Index(str, "Burger"))
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}
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```
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输出：
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@@ -88,33 +102,39 @@ Example 4.14 [index_in_string.go](examples/chapter_4/index_in_string.go)
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`Replace` 用于将字符串 `str` 中的前 `n` 个字符串 `old` 替换为字符串 `new`，并返回一个新的字符串，如果 `n = -1` 则替换所有字符串 `old` 为字符串 `new`：
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strings.Replace(str, old, new, n) string
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```go
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strings.Replace(str, old, new, n) string
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```
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## 4.7.5 统计字符串出现次数
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`Count` 用于计算字符串 `str` 在字符串 `s` 中出现的非重叠次数：
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strings.Count(s, str string) int
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```go
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strings.Count(s, str string) int
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```
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Example 4.15 [count_substring.go](examples/chapter_4/count_substring.go)
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示例 4.15 [count_substring.go](examples/chapter_4/count_substring.go)
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var str string = "Hello, how is it going, Hugo?"
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var manyG = "gggggggggg"
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fmt.Printf("Number of H's in %s is: ", str)
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fmt.Printf("%d\n", strings.Count(str, "H"))
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fmt.Printf("Number of double g's in %s is: ", manyG)
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fmt.Printf("%d\n", strings.Count(manyG, "gg"))
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}
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```go
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var str string = "Hello, how is it going, Hugo?"
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var manyG = "gggggggggg"
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fmt.Printf("Number of H's in %s is: ", str)
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fmt.Printf("%d\n", strings.Count(str, "H"))
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fmt.Printf("Number of double g's in %s is: ", manyG)
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fmt.Printf("%d\n", strings.Count(manyG, "gg"))
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}
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```
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输出：
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@@ -125,24 +145,28 @@ Example 4.15 [count_substring.go](examples/chapter_4/count_substring.go)
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`Repeat` 用于重复 `count` 次字符串 `s` 并返回一个新的字符串：
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strings.Repeat(s, count int) string
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```go
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strings.Repeat(s, count int) string
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```
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Example 4.16 [repeat_string.go](examples/chapter_4/repeat_string.go)
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示例 4.16 [repeat_string.go](examples/chapter_4/repeat_string.go)
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var origS string = "Hi there! "
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var newS string
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newS = strings.Repeat(origS, 3)
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fmt.Printf("The new repeated string is: %s\n", newS)
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}
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```go
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var origS string = "Hi there! "
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var newS string
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newS = strings.Repeat(origS, 3)
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fmt.Printf("The new repeated string is: %s\n", newS)
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}
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```
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输出：
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@@ -152,32 +176,38 @@ Example 4.16 [repeat_string.go](examples/chapter_4/repeat_string.go)
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`ToLower` 将字符串中的 Unicode 字符全部转换为相应的小写字符：
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strings.ToLower(s) string
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```go
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strings.ToLower(s) string
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```
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`ToUpper` 将字符串中的 Unicode 字符全部转换为相应的大写字符：
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strings.ToUpper(s) string
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```go
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strings.ToUpper(s) string
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```
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Example 4.17 [toupper_lower.go](examples/chapter_4/toupper_lower.go)
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示例 4.17 [toupper_lower.go](examples/chapter_4/toupper_lower.go)
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var orig string = "Hey, how are you George?"
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var lower string
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var upper string
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fmt.Printf("The original string is: %s\n", orig)
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lower = strings.ToLower(orig)
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fmt.Printf("The lowercase string is: %s\n", lower)
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upper = strings.ToUpper(orig)
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fmt.Printf("The uppercase string is: %s\n", upper)
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}
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```go
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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var orig string = "Hey, how are you George?"
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var lower string
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var upper string
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fmt.Printf("The original string is: %s\n", orig)
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lower = strings.ToLower(orig)
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fmt.Printf("The lowercase string is: %s\n", lower)
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upper = strings.ToUpper(orig)
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fmt.Printf("The uppercase string is: %s\n", upper)
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}
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```
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输出：
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@@ -201,35 +231,39 @@ Example 4.17 [toupper_lower.go](examples/chapter_4/toupper_lower.go)
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`Join` 用于将元素类型为 string 的 slice 使用分割符号来拼接组成一个字符串：
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Strings.Join(sl []string, sep string)
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```go
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Strings.Join(sl []string, sep string)
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```
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Example 4.18 [strings_splitjoin.go](examples/chapter_4/strings_splitjoin.go)
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示例 4.18 [strings_splitjoin.go](examples/chapter_4/strings_splitjoin.go)
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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str := "The quick brown fox jumps over the lazy dog"
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sl := strings.Fields(str)
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fmt.Printf("Splitted in slice: %v\n", sl)
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for _, val := range sl {
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fmt.Printf("%s - ", val)
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}
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fmt.Println()
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str2 := "GO1|The ABC of Go|25"
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sl2 := strings.Split(str2, "|")
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fmt.Printf("Splitted in slice: %v\n", sl2)
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for _, val := range sl2 {
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fmt.Printf("%s - ", val)
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}
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fmt.Println()
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str3 := strings.Join(sl2,";")
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fmt.Printf("sl2 joined by ;: %s\n", str3)
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```go
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package main
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import (
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"fmt"
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"strings"
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)
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func main() {
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str := "The quick brown fox jumps over the lazy dog"
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sl := strings.Fields(str)
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fmt.Printf("Splitted in slice: %v\n", sl)
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for _, val := range sl {
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fmt.Printf("%s - ", val)
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}
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fmt.Println()
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str2 := "GO1|The ABC of Go|25"
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sl2 := strings.Split(str2, "|")
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fmt.Printf("Splitted in slice: %v\n", sl2)
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for _, val := range sl2 {
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fmt.Printf("%s - ", val)
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}
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fmt.Println()
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str3 := strings.Join(sl2,";")
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fmt.Printf("sl2 joined by ;: %s\n", str3)
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}
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```
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输出：
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@@ -239,7 +273,7 @@ Example 4.18 [strings_splitjoin.go](examples/chapter_4/strings_splitjoin.go)
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GO1 - The ABC of Go - 25 -
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sl2 joined by ;: GO1;The ABC of Go;25
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其它有关字符串操作的文档请参阅官方文档 [http://golang.org/pkg/strings/](http://golang.org/pkg/strings/)（ ***译者注：国内用户可访问 [http://docs.studygolang.com/pkg/strings/](http://docs.studygolang.com/pkg/strings/)*** ）。
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其它有关字符串操作的文档请参阅官方文档 [http://golang.org/pkg/strings/](http://golang.org/pkg/strings/)（ **译者注：国内用户可访问 [该页面](http://docs.studygolang.com/pkg/strings/)** ）。
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## 4.7.11 从字符串中读取内容
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@@ -274,28 +308,30 @@ Example 4.18 [strings_splitjoin.go](examples/chapter_4/strings_splitjoin.go)
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在下面这个示例中，我们忽略可能出现的转换错误：
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Example 4.19 [string_conversion.go](examples/chapter_4/string_conversion.go)
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示例 4.19 [string_conversion.go](examples/chapter_4/string_conversion.go)
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package main
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import (
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"fmt"
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"strconv"
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)
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func main() {
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var orig string = "666"
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var an int
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var newS string
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fmt.Printf("The size of ints is: %d\n", strconv.IntSize)
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an, _ = strconv.Atoi(orig)
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fmt.Printf("The integer is: %d\n", an)
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an = an + 5
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newS = strconv.Itoa(an)
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fmt.Printf("The new string is: %s\n", newS)
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}
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```go
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package main
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import (
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"fmt"
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"strconv"
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)
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func main() {
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var orig string = "666"
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var an int
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var newS string
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fmt.Printf("The size of ints is: %d\n", strconv.IntSize)
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an, _ = strconv.Atoi(orig)
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fmt.Printf("The integer is: %d\n", an)
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an = an + 5
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newS = strconv.Itoa(an)
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fmt.Printf("The new string is: %s\n", newS)
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}
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```
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输出：
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@@ -305,7 +341,7 @@ Example 4.19 [string_conversion.go](examples/chapter_4/string_conversion.go)
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在第 5.1 节，我们将会利用 if 语句来对可能出现的错误进行分类处理。
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更多有关该包的讨论，请参阅官方文档 [http://golang.org/pkg/strconv/](http://golang.org/pkg/strconv/)（ ***译者注：国内用户可访问 [http://docs.studygolang.com/pkg/strconv/](http://docs.studygolang.com/pkg/strconv/)*** ）。
|
||||
更多有关该包的讨论，请参阅官方文档 [http://golang.org/pkg/strconv/](http://golang.org/pkg/strconv/)（ **译者注：国内用户可访问 [该页面](http://docs.studygolang.com/pkg/strconv/)** ）。
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## 链接
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||||
|
||||
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Reference in New Issue
Block a user