如何在 golang 中椭圆截断文本？

Question

我希望能够干净利落地剪切大于特定字符数的段落，而不需要在中间剪切一个单词。

例如：

It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English.

应该变成：

It is a long established fact that a reader will be distracted by the readable content ...

这是我想出的函数：

 func truncateText(s string, max int) string {
    if len(s) > max {
        r := 0
        for i := range s {
            r++
            if r > max {
                return s[:i]
            }
        }
    }
    return s
}

但它只是粗暴地切割文本。我想知道如何修改（或用更好的解决方案替换它）以便椭圆切割文本？

Answer 1

要根据空格等进行拆分，可以使用正则表达式：

func splitString(str string) []string {
    re := regexp.MustCompile("[\s\n\t\r ]+") //split according to \s, \t, \r, \t and whitespace. Edit this regex for other 'conditions'

    split := re.Split(str, -1)
    return split
}

func main() {
    var s = "It is a long\nestablished fact that a reader\nwill\nbe distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English."
    var maxLen = 40

    arr := splitString(s)

    totalLen := 0
    finalStr := ``
    for _, each := range arr {
        if (totalLen + len(each) > maxLen) {
            fmt.Print(strings.TrimSpace(finalStr) + `...`)
            break
        }
        totalLen += len(each)
        finalStr += each + ` `

    }
}

//老2

你可以做这样的事情：将你的字符串分成切片并循环遍历切片，直到你的字符串的总长度超过允许的最大长度。

    var s = "It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English."
    var maxLen = 30

    arr := strings.SplitAfter(s, ` `)

    totalLen := 0
    finalStr := ``
    for _, each := range arr {
        if (totalLen + len(each) > maxLen) {
            fmt.Print(strings.TrimSpace(finalStr) + `...`)
            break
        }
        totalLen += len(each)
        finalStr += each

    }

这是早已确立的事实...

//旧的错误答案
您必须使用字符串和切片：

    var s = "It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English."

    newS := s[:30 - 3] 
    newS += `...`
    fmt.Print(newS)

结果：It is a long established fa...

Answer 2

写的范围完全没有必要；就像现在一样，您的整个功能可能只是：

func truncateText(s string, max int) string {
    return s[:max]
}

太简单了，甚至不应该是一个函数；但当然它也会切断你说你不想要的话。所以你可以：

func truncateText(s string, max int) string {
    if max > len(s) {
        return s
    }
    return s[:strings.LastIndex(s[:max]," ")]
}

或者如果您想使用多个字符作为单词边界而不仅仅是空格：

func truncateText(s string, max int) string {
    if max > len(s) {
        return s
    }
    return s[:strings.LastIndexAny(s[:max]," .,:;-")]
}

Answer 3

切片字符串可能会出现问题，因为切片使用的是字节，而不是符文。然而，射程适用于符文：

lastSpaceIx:=-1
len:=0
for i,r:=range str {
  if unicode.IsSpace(r) {
     lastSpaceIx=i
  }
  len++
  if len>=max {
    if lastSpaceIx!=-1 {
        return str[:lastSpaceIx]+"..."
    }
    // If here, string is longer than max, but has no spaces
  }
}
// If here, string is shorter than max

如何在 golang 中椭圆截断文本？

How can I elliptically truncate text in golang?

string

truncate

go