[英]Replace using regular expression with replacement function
在Objective-C(適用於ios)中,我希望實現與AS3中相同的效果:
var test:String = "Abba";
var reg:RegExp = /(a)|(b)/g;
var replacement:Function = function (...args):String
{
var $1:String = args[1];//matched 'a'
var $2:String = args[2];//matched 'b'
if($1)
{
//replace a with -
return "-";
}
if ($2)
{
//replace b with +
return "+";
}
return null;
}
var result:String = test.replace(reg, replacement);//A++-
trace(test, result);//Abba A++-
換句話說,我希望能夠確定匹配的捕獲組並相應地替換它,我正在尋找有關enumerateMatchesInString的示例:但找不到能解決我的問題的任何東西。
enumerateMatchesInString:
為每個匹配調用一個帶有NSTextCheckingResult
的塊,而rangeAtIndex:idx
給出捕獲子組的范圍:
NSString *string = @"Abba";
NSString *pattern = @"(a)|(b)";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern
options:0
error:NULL];
NSMutableString *newString = [string mutableCopy];
[regex enumerateMatchesInString:string options:0 range:NSMakeRange(0, [string length])
usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
NSRange r1 = [result rangeAtIndex:1];
if (r1.location != NSNotFound) {
[newString replaceCharactersInRange:r1 withString:@"-"];
}
NSRange r2 = [result rangeAtIndex:2];
if (r2.location != NSNotFound) {
[newString replaceCharactersInRange:r2 withString:@"+"];
}
}];
NSLog(@"%@", newString);
// Output: A++-
如果替換字符串的長度與原始字符串的長度不同,那么它將變得稍微復雜一些,因為您必須跟蹤結果字符串的長度變化:
NSMutableString *newString = [string mutableCopy];
__block int offset = 0;
[regex enumerateMatchesInString:string options:0 range:NSMakeRange(0, [string length])
usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
NSRange r1 = [result rangeAtIndex:1];
if (r1.location != NSNotFound) {
r1.location += offset;
NSString *repl = @"---";
[newString replaceCharactersInRange:r1 withString:repl];
offset += [repl length] - r1.length;
}
NSRange r2 = [result rangeAtIndex:2];
if (r2.location != NSNotFound) {
r2.location += offset;
NSString *repl = @"++";
[newString replaceCharactersInRange:r2 withString:repl];
offset += [repl length] - r2.length;
}
}];
NSLog(@"%@", newString);
// Output: A++++---
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