How to convert a string to rune? - string

Question

Here is my code snippet:
var converter = map[rune]rune {//some data}
sample := "⌘こんにちは"
var tmp string
for _, runeValue := range sample {
fmt.Printf("%+q", runeValue)
tmp = fmt.Sprintf("%+q", runeValue)
}
The output of fmt.Printf("%+q", runeValue) is:
'\u2318'
'\u3053'
'\u3093'
'\u306b'
'\u3061'
'\u306f'
These value are literally rune but as the return type of Sprintf is string, I cannot use it in my map which is [rune]rune.
I was wondering how can I convert string to rune, or in other words how can I handle this problem?

Answer 1

A string is not a single rune, it may contain multiple runes. You may use a simple type conversion to convert a string to a []runes containing all its runes like []rune(sample).
The for range iterates over the runes of a string, so in your example runeValue is of type rune, you may use it in your converter map, e.g.:
var converter = map[rune]rune{}
sample := "⌘こんにちは"
for _, runeValue := range sample {
converter[runeValue] = runeValue
}
fmt.Println(converter)
But since rune is an alias for int32, printing the above converter map will print integer numbers, output will be:
map[8984:8984 12371:12371 12385:12385 12395:12395 12399:12399 12435:12435]
If you want to print characters, use the %c verb of fmt.Printf():
fmt.Printf("%c\n", converter)
Which will output:
map[⌘:⌘ こ:こ ち:ち に:に は:は ん:ん]
Try the examples on the Go Playground.
If you want to replace (switch) certain runes in a string, use the strings.Map() function, for example:
sample := "⌘こんにちは"
result := strings.Map(func(r rune) rune {
if r == '⌘' {
return 'a'
}
if r == 'こ' {
return 'b'
}
return r
}, sample)
fmt.Println(result)
Which outputs (try it on the Go Playground):
abんにちは
If you want the replacements defined by a converter map:
var converter = map[rune]rune{
'⌘': 'a',
'こ': 'b',
}
sample := "⌘こんにちは"
result := strings.Map(func(r rune) rune {
if c, ok := converter[r]; ok {
return c
}
return r
}, sample)
fmt.Println(result)
This outputs the same. Try this one on the Go Playground.

Answer 2

Convert string to rune array:
runeArray := []rune("пример")