文字列からあ行など取得する

仕様

• 英語は全角でも半角でも半角に
• カタカナもひらがなに
• 記号などはブランク

ソース

objective-c

- (NSString *)getJapaneseLine:(NSString *)aString
{
    if (aString.length == 0) {
        return @"";
    }

    NSString *uppercaseString = [aString uppercaseString];
    NSMutableString *halfString = [uppercaseString mutableCopy];
    CFStringTransform((CFMutableStringRef)halfString, NULL, kCFStringTransformFullwidthHalfwidth, FALSE);
    NSMutableString *kanaString = [halfString mutableCopy];
    CFStringTransform((CFMutableStringRef)kanaString, NULL, kCFStringTransformHiraganaKatakana, TRUE);
    unichar uc = [kanaString characterAtIndex:0];
    
    if (uc >= 0x3041 && uc <= 0x304A) {
        return @"あ";
    } else if (uc >= 0x304B && uc <= 0x3054) {
        return @"か";
    } else if (uc >= 0x3055 && uc <= 0x305E) {
        return @"さ";
    } else if (uc >= 0x305F && uc <= 0x3069) {
        return @"た";
    } else if (uc >= 0x306A && uc <= 0x306E) {
        return @"な";
    } else if (uc >= 0x306F && uc <= 0x307D) {
        return @"は";
    } else if (uc >= 0x307E && uc <= 0x3082) {
        return @"ま";
    } else if (uc >= 0x3083 && uc <= 0x3088) {
        return @"や";
    } else if (uc >= 0x3089 && uc <= 0x308D) {
        return @"ら";
    } else if (uc >= 0x308F && uc <= 0x3093) {
        return @"わ";
    } else if (uc >= 0x0041 && uc <= 0x005A) {
        // A-Z
        return [NSString stringWithFormat:@"%C", uc];
    } else {
        // その他
        return @"";
    }
}

swift

func getJapaneseLine(aString: String) -> String {
	if line.isEmpty {
		return "";
	}
	
	var keyString = String(aString[aString.startIndex]).uppercaseString
	var halfString = NSMutableString(string: keyString) as CFMutableString
	CFStringTransform(halfString, nil, kCFStringTransformFullwidthHalfwidth, false)
	var kanaString = NSMutableString(string: halfString) as CFMutableString
	CFStringTransform(kanaString, nil, kCFStringTransformHiraganaKatakana, true)
	keyString = kanaString as String
	let c = first(keyString.unicodeScalars)!.value

	if c >= 0x3041 && c <= 0x304A {
		return "あ"
	} else if c >= 0x304B && c <= 0x3054 {
		return "か"
	} else if c >= 0x3055 && c <= 0x305E {
		return "さ"
	} else if c >= 0x305F && c <= 0x3069 {
		return "た"
	} else if c >= 0x306A && c <= 0x306E {
		return "な"
	} else if c >= 0x306F && c <= 0x307D {
		return "は"
	} else if c >= 0x307E && c <= 0x3082 {
		return "ま"
	} else if c >= 0x3083 && c <= 0x3088 {
		return "や"
	} else if c >= 0x3089 && c <= 0x308D {
		return "ら"
	} else if c >= 0x308F && c <= 0x3093 {
		return "わ"
	} else if c >= 0x0041 && c <= 0x005A {
		// A-Z
		return String(format: "%C", c)
	} else {
		// その他
		return "";
	}
}