如何在Objective C（NSRegularExpression）中编写正则表达式？ [英] How to write regular expressions in Objective C (NSRegularExpression)?
问题描述
当我在PHP中测试它时，我有这个正则表达式工作，但它在目标C中不起作用：
（？ ：www\） - [α-ZA-Z0-9 - ] {2,63}; - ）\（（（（！）（小于？！）：？[A-ZA-Z0 -9] {2，}）？（？：\。[a-zA-Z0-9] {2，}）？）
我试图逃避转义字符，但这也无济于事。我应该逃避任何其他角色吗？
这是我在目标C中的代码：
NSMutableString * searchingString = [NSMutableString stringWithString：@domain-name.tld.tld2];
NSError * error = nil;
NSRegularExpression * regex = [NSRegularExpression regularExpressionWithPattern：@（？：www \\。）？（（？！ - ）[a-zA-Z0-9 - ] {2,63} （小于 - ？！））\\。？。（（？：[A-ZA-Z0-9] {2，}）（?: \\ [A-ZA-Z0-9] {2，}）？）options：0 error：& error];
NSArray * matches = [regex matchesInString：searchingString options：0 range：NSMakeRange（0，[searchingString length]）];
for（NSTextCheckingResult *匹配匹配）
{
NSString * matchText = [searchingString substringWithRange：[match range]];
NSLog（@match：％@，matchText）;
}
- 更新 -
这个正则表达式返回（在PHP中）值为domain-name和tld.tld2的数组，但在Objective C中我只得到一个值：domain-name.tld.tld2
- 更新2 -
此正则表达式从字符串中提取域名和TLD：
- domain.com =（domain，com）
- domain.co.uk =（domain，co.uk ）
- -test-domain.co.u =（test-domain，co）
- -test-domain.co.uk- =（ test-domain，co.uk）
- -test-domain.co.uk =（test-domain，co）
- -test-domain .co-m =（test-domain）
- -test-domain-.co.uk =（test-domain）
它采用有效的域名（不是以' - '开头或结尾，长度在2到63个字符之间），如果部分有效，则最多为TLD的两个部分（至少两个）只包含字母和数字的字符）
希望这个解释有所帮助。
A NSTextCheckingResult 通过索引获得多个项目。
[match rangeAtIndex：0]; 是完全匹配。
[match rangeAtIndex：1]; （如果存在）是第一个捕获组匹配。
等。
您可以使用以下内容：
NSString * searchingString = @domain-name.tld.tld2;
NSRange searchingRange = NSMakeRange（0，[searchingString length]）;
NSString * pattern = @（？：www \\。）？（（？！ - ）[a-zA-Z0-9 - ] {2,63}（？<！ - ）） \\。？（（？：？？[A-ZA-Z0-9] {2，}）（?: \\ [A-ZA-Z0-9] {2，}）） ;
NSError * error = nil;
NSRegularExpression * regex = [NSRegularExpression regularExpressionWithPattern：pattern options：0 error：& error];
NSArray * matches = [regex matchesInString：searchingString options：0 range：searchingRange];
for（NSTextCheckingResult *匹配中匹配）{
NSString * matchText = [searchingString substringWithRange：[match range]];
NSLog（@match：％@，matchText）;
NSRange group1 = [match rangeAtIndex：1];
NSRange group2 = [match rangeAtIndex：2];
NSLog（@group1：％@，[searchingString substringWithRange：group1]）;
NSLog（@group2：％@，[searchingString substringWithRange：group2]）;
}
NSLog输出：
< blockquote>
匹配：domain-name.tld.tld2
domain-name
tld.tld2
测试匹配范围是否有效。
在这种情况下更简单：
NSString * searchingString = @domain-name.tld.tld2;
NSRange searchingRange = NSMakeRange（0，[searchingString length]）;
NSString * pattern = @（？：www \\。）？（（？！ - ）[a-zA-Z0-9 - ] {2,63}（？<！ - ）） \\。？（（？：？？[A-ZA-Z0-9] {2，}）（?: \\ [A-ZA-Z0-9] {2，}）） ;
NSError * error = nil;
NSRegularExpression * regex = [NSRegularExpression regularExpressionWithPattern：pattern options：0 error：& error];
NSTextCheckingResult * match = [regex firstMatchInString：searchingString options：0 range：searchingRange];
NSLog（@group1：％@，[searchingString substringWithRange：[match rangeAtIndex：1]]）;
NSLog（@group2：％@，[searchingString substringWithRange：[match rangeAtIndex：2]]）;
Swift 3.0：
let searchingString =domain-name.tld.tld2
让nsSearchedString = searchingString为NSString
let searchingRange = NSMakeRange（0，searchingString.characters.count）
let pattern =（？：www \\。）？（（？！ - ）[a-zA-Z0-9 - ] {2,63} （小于 - ？！））\\。？。（（？：[A-ZA-Z0-9] {2，}）（?: \\ [A-ZA-Z0-9] {2，}）？）
do {
let regex = try NSRegularExpression（pattern：pattern，options：[]）
let matches = regex.matches（in： searchingString，options：[]，range：searchingRange）
匹配匹配{
let matchText = nsSearchedString.substring（with：match.range）;
print（match：\（matchText））;
let group1：NSRange = match.rangeAt（1）
let matchText1 = nsSearchedString.substring（with：group1）
print（matchText1：\（matchText1））
let group2 = match.rangeAt（2）
let matchText2 = nsSearchedString.substring（with：group2）
print（matchText2：\（matchText2））
}
}将错误视为NSError {
print（error.localizedDescription）
}
打印输出：
匹配：domain-name.tld.tld2
matchText1 ：域名
matchText2：tld.tld2
在这种情况下更简单：
do {
let regex = try NSRegularExpression（pattern：pattern，options：[]）
let match = regex.firstMatch （in：searchingString，options：[]，range：searchingRange）
let matchText1 = nsSearchedString.substring（with：match！.rangeAt（1））
print（ma tchText1：\（matchText1））
let matchText2 = nsSearchedString.substring（with：match！.rangeAt（2））
print（matchText2：\（matchText2））
}将错误视为NSError {
print（error.localizedDescription）
}
打印输出：
matchText1：domain-name
matchText2：tld。 tld2
I have this regex working when I test it in PHP but it doesn't work in Objective C:
(?:www\.)?((?!-)[a-zA-Z0-9-]{2,63}(?<!-))\.?((?:[a-zA-Z0-9]{2,})?(?:\.[a-zA-Z0-9]{2,})?)
I tried escaping the escape characters but that doesn't help either. Should I escape any other character?
This is my code in Objective C:
NSMutableString *searchedString = [NSMutableString stringWithString:@"domain-name.tld.tld2"];
NSError* error = nil;
NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:@"(?:www\\.)?((?!-)[a-zA-Z0-9-]{2,63}(?<!-))\\.?((?:[a-zA-Z0-9]{2,})?(?:\\.[a-zA-Z0-9]{2,})?)" options:0 error:&error];
NSArray* matches = [regex matchesInString:searchedString options:0 range:NSMakeRange(0, [searchedString length])];
for ( NSTextCheckingResult* match in matches )
{
NSString* matchText = [searchedString substringWithRange:[match range]];
NSLog(@"match: %@", matchText);
}
-- UPDATE --
This regex returns (in PHP) the array with values "domain-name" and "tld.tld2" but in Objective C i get only one value: "domain-name.tld.tld2"
-- UPDATE 2 --
This regex extracts 'domain name' and 'TLD' from the string:
- domain.com = (domain, com)
- domain.co.uk = (domain, co.uk)
- -test-domain.co.u = (test-domain, co)
- -test-domain.co.uk- = (test-domain, co.uk)
- -test-domain.co.u-k = (test-domain, co)
- -test-domain.co-m = (test-domain)
- -test-domain-.co.uk = (test-domain)
it takes the valid domain name (not starting or ending with '-' and between 2 and 63 characters long), and up to two parts of a TLD if the parts are valid (at least two characters long containing only letters and numbers)
Hope this explanation helps.
A NSTextCheckingResult has multiple items obtained by indexing into it.
[match rangeAtIndex:0]; is the full match.
[match rangeAtIndex:1]; (if it exists) is the first capture group match.
etc.
You can use something like this:
NSString *searchedString = @"domain-name.tld.tld2";
NSRange searchedRange = NSMakeRange(0, [searchedString length]);
NSString *pattern = @"(?:www\\.)?((?!-)[a-zA-Z0-9-]{2,63}(?<!-))\\.?((?:[a-zA-Z0-9]{2,})?(?:\\.[a-zA-Z0-9]{2,})?)";
NSError *error = nil;
NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern: pattern options:0 error:&error];
NSArray* matches = [regex matchesInString:searchedString options:0 range: searchedRange];
for (NSTextCheckingResult* match in matches) {
NSString* matchText = [searchedString substringWithRange:[match range]];
NSLog(@"match: %@", matchText);
NSRange group1 = [match rangeAtIndex:1];
NSRange group2 = [match rangeAtIndex:2];
NSLog(@"group1: %@", [searchedString substringWithRange:group1]);
NSLog(@"group2: %@", [searchedString substringWithRange:group2]);
}
NSLog output:
match: domain-name.tld.tld2
domain-name
tld.tld2
Do test that the match ranges are valid.
More simply in this case:
NSString *searchedString = @"domain-name.tld.tld2";
NSRange searchedRange = NSMakeRange(0, [searchedString length]);
NSString *pattern = @"(?:www\\.)?((?!-)[a-zA-Z0-9-]{2,63}(?<!-))\\.?((?:[a-zA-Z0-9]{2,})?(?:\\.[a-zA-Z0-9]{2,})?)";
NSError *error = nil;
NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:pattern options:0 error:&error];
NSTextCheckingResult *match = [regex firstMatchInString:searchedString options:0 range: searchedRange];
NSLog(@"group1: %@", [searchedString substringWithRange:[match rangeAtIndex:1]]);
NSLog(@"group2: %@", [searchedString substringWithRange:[match rangeAtIndex:2]]);
Swift 3.0:
let searchedString = "domain-name.tld.tld2"
let nsSearchedString = searchedString as NSString
let searchedRange = NSMakeRange(0, searchedString.characters.count)
let pattern = "(?:www\\.)?((?!-)[a-zA-Z0-9-]{2,63}(?<!-))\\.?((?:[a-zA-Z0-9]{2,})?(?:\\.[a-zA-Z0-9]{2,})?)"
do {
let regex = try NSRegularExpression(pattern:pattern, options: [])
let matches = regex.matches(in:searchedString, options:[], range:searchedRange)
for match in matches {
let matchText = nsSearchedString.substring(with:match.range);
print("match: \(matchText)");
let group1 : NSRange = match.rangeAt(1)
let matchText1 = nsSearchedString.substring(with: group1)
print("matchText1: \(matchText1)")
let group2 = match.rangeAt(2)
let matchText2 = nsSearchedString.substring(with: group2)
print("matchText2: \(matchText2)")
}
} catch let error as NSError {
print(error.localizedDescription)
}
print output:
match: domain-name.tld.tld2
matchText1: domain-name
matchText2: tld.tld2
More simply in this case:
do {
let regex = try NSRegularExpression(pattern:pattern, options: [])
let match = regex.firstMatch(in:searchedString, options:[], range:searchedRange)
let matchText1 = nsSearchedString.substring(with: match!.rangeAt(1))
print("matchText1: \(matchText1)")
let matchText2 = nsSearchedString.substring(with: match!.rangeAt(2))
print("matchText2: \(matchText2)")
} catch let error as NSError {
print(error.localizedDescription)
}
print output:
matchText1: domain-name
matchText2: tld.tld2
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