我希望能够干净地剪切大于一定字符数的段落，而不会在中间剪切一个单词。
例如：
读者会被 查看其布局时页面的可读内容。的点 使用 Lorem Ipsum 是它具有或多或少的正态分布 字母，而不是使用“这里的内容，这里的内容”，使它 看起来像可读的英语。
应该变成：
读者会被 可读的内容...
这是我想出的功能：
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
}
但它只是粗暴地削减了文本。我想知道如何修改（或用更好的解决方案替换它）以椭圆地剪切文本？
【问题讨论】：
切片字符串可能会出现问题，因为切片适用于字节，而不是符文。然而，范围适用于符文：
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
【讨论】：
这个范围是完全没有必要写的；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]
}
这么简单，它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单词。因此，您可以：
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]," .,:;-")]
}
【讨论】：
max时出现恐慌。
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
您可以执行以下操作：将字符串拆分为切片并循环遍历切片，直到字符串的总长度超过最大允许长度。
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
}
这是一个早已确立的事实......
//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...
【讨论】：