一些有趣的事

\U0000202E (2016.6.3)

今天在项目中遇到一个很有意思的事情，测试在编辑用户昵称的时候，不知道从哪里copy了一个特殊字符\U0000202E，然后我们在label上面显示的时候就出问题了，本来应该是wind参加了活动，结果变成了wind动活了加参，当时我就懵逼了，后面断点调试，发现字符串为wind\U0000202E参加了活动。后面我在Google上搜索\U0000202E，只搜到了两条结果

http://permalink.gmane.org/gmane.comp.lib.regexp.tre/39 https://github.com/nbjahan/launchbar-unisym/blob/master/src/2000-206f_general_punctuation.go

然后我把第一条链接里面的所提及用demo运行效果出来了。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
    }
    static NSArray *charArray = nil;
    if (!charArray) {
        charArray = @[@"\U0000200E", @"\U0000200F", @"\U0000200B", @"\U0000202A", @"\U0000202E", @"\U00002060", @"\U0000206A", @"\U0000206F"];
    }
    if (indexPath.row < [charArray count]) {
        NSString *text = [NSString stringWithFormat:@"%@+%@-%@", @(indexPath.row + 1), charArray[indexPath.row], @"一颗赛艇"];
        NSString *length = @(text.length).stringValue;
        NSInteger index = [text rangeOfString:charArray[indexPath.row]].location;
        cell.textLabel.text = text;
        cell.detailTextLabel.text = [NSString stringWithFormat:@"length:%@ index:%@", length, @(index)];
    }
    return cell;
}

下面是第二个链接的东西，是一个数组，关于unicode码以及它的相关含义。

func init() {

chars["02000"] = [][2]string{

// {"En Quad", "\U00002000"},

// {"Em Quad", "\U00002001"},

// {"En Space", "\U00002002"},

// {"Em Space", "\U00002003"},

// {"Three-Per-Em Space", "\U00002004"},

// {"Four-Per-Em Space", "\U00002005"},

// {"Six-Per-Em Space", "\U00002006"},

// {"Figure Space", "\U00002007"},

// {"Punctuation Space", "\U00002008"},

// {"Thin Space", "\U00002009"},

// {"Hair Space", "\U0000200a"},

// {"Zero Width Space", "\U0000200b"},

// {"Zero Width Non-Joiner", "\U0000200c"},

// {"Zero Width Joiner", "\U0000200d"},

// {"Left-To-Right Mark", "\U0000200e"},

// {"Right-To-Left Mark", "\U0000200f"},

{"Hyphen", "\U00002010"},

{"Non-Breaking Hyphen", "\U00002011"},

{"Figure Dash", "\U00002012"},

{"En Dash", "\U00002013"},

{"Em Dash", "\U00002014"},

{"Horizontal Bar", "\U00002015"},

{"Double Vertical Line", "\U00002016"},

{"Double Low Line", "\U00002017"},

{"Left Single Quotation Mark", "\U00002018"},

{"Right Single Quotation Mark", "\U00002019"},

{"Single Low-9 Quotation Mark", "\U0000201a"},

{"Single High-Reversed-9 Quotation Mark", "\U0000201b"},

{"Left Double Quotation Mark", "\U0000201c"},

{"Right Double Quotation Mark", "\U0000201d"},

{"Double Low-9 Quotation Mark", "\U0000201e"},

{"Double High-Reversed-9 Quotation Mark", "\U0000201f"},

{"Dagger", "\U00002020"},

{"Double Dagger", "\U00002021"},

{"Bullet", "\U00002022"},

{"Triangular Bullet", "\U00002023"},

{"One Dot Leader", "\U00002024"},

{"Two Dot Leader", "\U00002025"},

{"Horizontal Ellipsis", "\U00002026"},

{"Hyphenation Point", "\U00002027"},

// {"Line Separator", "\U00002028"},

// {"Paragraph Separator", "\U00002029"},

// {"Left-To-Right Embedding", "\U0000202a"},

// {"Right-To-Left Embedding", "\U0000202b"},

// {"Pop Directional Formatting", "\U0000202c"},

// {"Left-To-Right Override", "\U0000202d"},

// {"Right-To-Left Override", "\U0000202e"},

// {"Narrow No-Break Space", "\U0000202f"},

{"Per Mille Sign", "\U00002030"},

{"Per Ten Thousand Sign", "\U00002031"},

{"Prime", "\U00002032"},

{"Double Prime", "\U00002033"},

{"Triple Prime", "\U00002034"},

{"Reversed Prime", "\U00002035"},

{"Reversed Double Prime", "\U00002036"},

{"Reversed Triple Prime", "\U00002037"},

{"Caret", "\U00002038"},

{"Single Left-Pointing Angle Quotation Mark", "\U00002039"},

{"Single Right-Pointing Angle Quotation Mark", "\U0000203a"},

{"Reference Mark", "\U0000203b"},

{"Double Exclamation Mark", "\U0000203c"},

{"Interrobang", "\U0000203d"},

{"Overline", "\U0000203e"},

{"Undertie", "\U0000203f"},

{"Character Tie", "\U00002040"},

{"Caret Insertion Point", "\U00002041"},

{"Asterism", "\U00002042"},

{"Hyphen Bullet", "\U00002043"},

{"Fraction Slash", "\U00002044"},

{"Left Square Bracket With Quill", "\U00002045"},

{"Right Square Bracket With Quill", "\U00002046"},

{"Double Question Mark", "\U00002047"},

{"Question Exclamation Mark", "\U00002048"},

{"Exclamation Question Mark", "\U00002049"},

{"Tironian Sign Et", "\U0000204a"},

{"Reversed Pilcrow Sign", "\U0000204b"},

{"Black Leftwards Bullet", "\U0000204c"},

{"Black Rightwards Bullet", "\U0000204d"},

{"Low Asterisk", "\U0000204e"},

{"Reversed Semicolon", "\U0000204f"},

{"Close Up", "\U00002050"},

{"Two Asterisks Aligned Vertically", "\U00002051"},

{"Commercial Minus Sign", "\U00002052"},

{"Swung Dash", "\U00002053"},

{"Inverted Undertie", "\U00002054"},

{"Flower Punctuation Mark", "\U00002055"},

{"Three Dot Punctuation", "\U00002056"},

{"Quadruple Prime", "\U00002057"},

{"Four Dot Punctuation", "\U00002058"},

{"Five Dot Punctuation", "\U00002059"},

{"Two Dot Punctuation", "\U0000205a"},

{"Four Dot Mark", "\U0000205b"},

{"Dotted Cross", "\U0000205c"},

{"Tricolon", "\U0000205d"},

{"Vertical Four Dots", "\U0000205e"},

// {"Medium Mathematical Space", "\U0000205f"},

// {"Word Joiner", "\U00002060"},

{"Function Application", "\U00002061"},

{"Invisible Times", "\U00002062"},

{"Invisible Separator", "\U00002063"},

{"Invisible Plus", "\U00002064"},

// {"Left-To-Right Isolate", "\U00002066"},

// {"Right-To-Left Isolate", "\U00002067"},

// {"First Strong Isolate", "\U00002068"},

// {"Pop Directional Isolate", "\U00002069"},

// {"Inhibit Symmetric Swapping", "\U0000206a"},

// {"Activate Symmetric Swapping", "\U0000206b"},

// {"Inhibit Arabic Form Shaping", "\U0000206c"},

// {"Activate Arabic Form Shaping", "\U0000206d"},

// {"National Digit Shapes", "\U0000206e"},

}

}

平常反转一个字符串的时候，我是将它一个一个字符的处理

    NSString *string = @"一颗赛特123";
    NSLog(@"string1:%@",string);
    NSMutableString *reverseString = [@"" mutableCopy];
    for (NSInteger i = (string.length - 1); i > -1; i--) {
        [reverseString appendString:[NSString stringWithFormat:@"%@", [string substringWithRange:NSMakeRange(i, 1)]]];
    }
    NSLog(@"reverseString:%@",reverseString);

// string1:一颗赛特123
// reverseString:321特赛颗一

那现在就可以这样做了

    NSString *string = @"一颗赛特123";
    NSLog(@"string1:%@",string);
    NSString *tmpString = [NSString stringWithFormat:@"\U0000202E%@",string];
    NSString *reverseString = [tmpString substringFromIndex:1];
    NSLog(@"tmpString:%@ \nreverseString:%@",tmpString,reverseString);

// string1:一颗赛特123
// tmpString:321特赛颗一
// reverseString:一颗赛特123

好吧，字符串里面必须要包含\U0000202E字符，实际项目中如果需要计算长度的话，那这样子做是行不通的。

这种Unicode编码有的时候还是挺有用的，最近在做群聊@功能就用到了\u2005特殊空格字符（听说微信就是这么做的）。
https://github.com/liuwons/wxBot/issues/10