Counting characters in golang string
<p>I am trying to count "characters" in go. That is, if a string contains one printable "glyph", or "composed character" (or what someone would ordinarily think of as a character), I want it to count 1. For example, the string "Hello, 世界", should count 11, since there are 11 characters, and a human would look at this and say there are 11 glyphs.</p>

<p>utf8.RuneCountInString() works well in most cases, including ascii, accents, asian characters and even emojis. However, as I understand it runes correspond to code points, not characters. When I try to use basic emojis it works, but when I use emojis that have different skin tones, I get the wrong count: <a href="https://play.golang.org/p/aFIGsB6MsO" rel="noreferrer">https://play.golang.org/p/aFIGsB6MsO</a></p>

<p>From what I read <a href="https://stackoverflow.com/questions/36569018/can-a-character-span-multiple-runes-in-go">here</a> and <a href="https://blog.golang.org/normalization" rel="noreferrer">here</a>  the following should work, but I still don't seem to be getting the right results (it over-counts):</p>

<pre><code>func CountCharactersInString(str string) int {
    var ia norm.Iter
    ia.InitString(norm.NFC, str)
    nc := 0
    for !ia.Done() {
        nc = nc + 1
        ia.Next()
    }
    return nc
}
</code></pre>

<p>This doesn't work either:</p>

<pre><code>func GraphemeCountInString(str string) int {
    re := regexp.MustCompile("\\PM\\pM*|.")
    return len(re.FindAllString(str, -1))
}
</code></pre>

<p>I am looking for something similar to this in Objective C:</p>

<pre><code>+ (NSInteger)countCharactersInString:(NSString *) string {
    // --- Calculate the number of characters enterd by user and update character count label
    NSInteger count = 0;
    NSUInteger index = 0;
    while (index &lt; string.length) {
        NSRange range = [string rangeOfComposedCharacterSequenceAtIndex:index];
        count++;
        index += range.length;
    }
    return count;
 }
</code></pre>