Join

This Go method combines a slice of strings into a single string. We pass it the slice as the first argument. The delimiter to be inserted is the second.

With join we must pass 2 arguments. To join with no delimiter (convert a string slice to a string) we can use an empty string as the delimiter. This works well.

First example

Here we create an empty string slice and then append 3 strings. We join those strings together with ellipses. The Join() func in Go is like those in many other languages.

package main

import (
    "fmt"
    "strings"
)

func main() {
    // Create a slice and append three strings to it.
    values := []string{}
    values = append(values, "cat")
    values = append(values, "dog")
    values = append(values, "bird")

    // Join three strings into one.
    result := strings.Join(values, "...")
    fmt.Println(result)
}
cat...dog...bird

No delimiter

Suppose we have a slice of strings, and each string is the same length. We can join these strings together and then extract them based on their length alone.

package main

import (
    "fmt"
    "strings"
)

func main() {
    // A slice of 3 strings.
    values := []string{"a", "b", "c"}
    // Join with no separator to create a compact string.
    joined := strings.Join(values, "")
    fmt.Println(joined)
}
abc

When we join a slice together, we lose some information about the individual strings. Data loss can occur if we have a delimiter inside one of the strings. This must be tested for.