搜索不区分大小写并替换整个单词

Question

I need to search for specific pattern and only if its whole word or combination of few words I should replace it. I am struggling with metacharacters Say my search pattern is: "corp." Should be replaced with "Corporation" so when input: "SS Corp. Ltd" expected output is "SS Corporation Ltd"

I tried using:

package main

import (
    "fmt"
    "regexp"
)

func main() {
    search :="corp."
    rep := "Corporation"
    sample :="SS Corp. LTd"
    var re = regexp.MustCompile(`(^|[^_])\b`+search+`\b([^_]|$)`)
    s2 := re.ReplaceAllString(sample, "${1}"+rep+"${2}")
}

Answer 1

There are several problems here:

1. An unescaped . matches any char other than line break, it must be escaped. Since you are building the pattern dynamically, use regexp.QuoteMeta
2. As a \b word boundary after . requires a word char, you can't expect a\.\b to match a. b. Replace the boundaries with (^|[^\p{L}0-9_]) for the leading boundary and ([^\p{L}0-9_]|$) for the trailing boundary.
3. At this stage, the pattern will be built like this: `(?i)(^|[^\p{L}0-9_])`+regexp.QuoteMeta(search)+`([^\p{L}0-9_]|$)`, but since both the boundaries are consuming patterns, you will never match consecutive matches (corp. corp. will result in Corporation corp., the second one won't be replaced). You should repeat replacing until no regex match can be found.
4. And to make the pattern case insensitive, use (?i) inline modifier at the pattern start.

The regex will look like

(?i)(^|[^\p{L}0-9_])corp\.([^\p{L}0-9_]|$)

See the regex demo.

Details

• (?i) - case insensitive modifier
• (^|[^\p{L}0-9_]) - either start of string or a char other than a Unicode letter, ASCII digit and _
• corp\. - a corp. substring
• ([^\p{L}0-9_]|$) - either a char other than a Unicode letter, ASCII digit and _ or end of string

See this example demo:

package main

import (
    "fmt"
    "regexp"
)

func main() {
    search :="corp."
    rep := "Corporation"
    sample :="SS Corp. Corp. LTd"
    var re = regexp.MustCompile(`(?i)(^|[^\p{L}0-9_])`+regexp.QuoteMeta(search)+`([^\p{L}0-9_]|$)`)
    fmt.Println(re)
    var res = sample
    for re.MatchString(res) {
        res = ReplaceWith(res, re, "${1}"+rep+"${2}")
    }
    fmt.Println(res)
}

func ReplaceWith(s string, re *regexp.Regexp, repl string) string {
    return re.ReplaceAllString(s, repl)
}

Result: SS Corporation Corporation LTd.