There are two main ways to replace substrings in strings in Go language. First, use the strings.Replace function for a simple replacement, with the syntax as strings.Replace(original, old, new, n), where n represents the number of replacements, and set to -1 to replace all matches; second, use the regexp package to handle complex pattern replacement, the steps include compiling the regular expression and calling the ReplaceAllString or ReplaceAllStringFunc method. In addition, due to the immutable string nature of Go, a new string is generated for each operation. Therefore, it is recommended to use strings.Builder or bytes.Buffer to improve performance for frequently modified scenarios.
Replacing substrings in strings in Go is not difficult, but some details need to be paid attention to. Go's strings are immutable, so a new string is generated for each operation. The most common method is to use strings.Replace
in the standard library or a more flexible regular expression.

Replace substrings with strings.Replace
This is the most basic and common practice. If you just need to simply replace a fixed substring, this function is enough.

The syntax is as follows:
strings.Replace(original, old, new, n)
-
original
is the original string. -
old
is what to be replaced. -
new
is the replaced content. -
n
is the number of replacements. If set to-1
, all matches will be replaced.
For example:

s := "hello world, hello golang" newS := strings.Replace(s, "hello", "hi", -1) // Output: hi world, hi golang
If you just want to replace the first substring, just change -1
to 1
.
This method is suitable for most simple scenarios, but if you want to deal with complex patterns (such as ignoring case and replacing multiple similar structures), you have to use regularity.
Replace with regular expressions (regexp)
When you want to replace not a fixed string, but a certain pattern, you can consider using regexp
package.
The steps are roughly like this:
- Compile a regular expression.
- Call the
ReplaceAllString
method to replace.
For example, you want to replace all numbers with #
:
import "regexp" s := "abc123def456" re := regexp.MustCompile(`\d `) result := re.ReplaceAllString(s, "#") // Output: abc#def#
You can also use ReplaceAllStringFunc
to do more complex logic, such as changing the matching part and replacing it.
Note: Regular expression compilation may go wrong. If you are not sure if the expression is correct, you can use regexp.Compile
and check for errors.
Pay attention to the immutable characteristics of strings
Go's strings are read-only, so whether it is strings.Replace
or regexp.ReplaceAllString
, a new string will be returned. If you plan to modify it multiple times, it is recommended to use strings.Builder
or bytes.Buffer
to improve performance.
for example:
var b strings.Builder b.WriteString("start") b.WriteString(modified) b.WriteString("end") final := b.String()
This avoids frequent creation of temporary string objects, especially when looping or large text processing is more efficient.
Basically that's it. Although there is no syntax sugar in Go that can be solved in one line like other languages, the standard library has provided clear and efficient tools.
The above is the detailed content of How to replace a substring in golang. For more information, please follow other related articles on the PHP Chinese website!

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