ios - 使用正则表达式提取两个标记之间的文本

Question

简单的正则表达式问题。我有以下格式的字符串:

[page]
Some text with multi line.
[page/]

[page]
Another text with multi line.
[page/]

[page]
Third text with multi line.
[page/]

提取[page]和[page/]之间文本的正则表达式是什么？

我正在使用这段代码，但我只得到了第一个匹配项。

NSString *path = [[NSBundle mainBundle] pathForResource:@"File" ofType:@"txt"];
NSString *mainText = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];

NSError *error = NULL;
NSRange range = NSMakeRange(0, mainText.length);

   NSString *pattern = [NSString stringWithFormat:@"(?<=\\[page])(?s)(.*?)(?=\\[page/])"];
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:NSRegularExpressionCaseInsensitive error:&error];
        NSRange rangeOfFirstMatch = [regex rangeOfFirstMatchInString:mainText options:0 range:range];


        if (!NSEqualRanges(rangeOfFirstMatch, NSMakeRange(NSNotFound, 0))) {
            NSString *substringForFirstMatch = [mainText substringWithRange:rangeOfFirstMatch];
            NSLog(@"sub: %@", substringForFirstMatch);
        }

除了 NSArray 中每个匹配项的文本，我怎样才能做到这一点？

Answer 1

您可以使用 matchesInString:options:range:，它返回一个匹配数组作为 NSTextCheckingResults:

    NSString *pattern = [NSString stringWithFormat:@"(?<=\\[page\\])(.*?)(?=\\[page\\/\\])"];
    NSUInteger options = NSRegularExpressionCaseInsensitive | NSRegularExpressionDotMatchesLineSeparators;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:options error:&error];

    for (NSTextCheckingResult* result in [regex matchesInString:INPUT_STRING 
                                                    options:0 
                                                      range:NSMakeRange(0, [input_string_length])])
    {
      // further code
    }