Question

iphone xcode objective-c：

我有一个包含大量文字的字符串..

我想检测@“hello”在字符串中的次数...

我知道如何检测它是否存在，但我如何检测它在字符串中出现的次数？

Answer 1

您可以使用正则表达式：

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"\\bhello\\b" options:NSRegularExpressionCaseInsensitive error:NULL];
NSUInteger numberOfMatches = [regex numberOfMatchesInString:someString options:0 range:NSMakeRange(0, [string length])];

Answer 2

NSUInteger count = 0, length = [yourString length];
NSRange range = NSMakeRange(0, length); 
while(range.location != NSNotFound)
{
  range = [yourString rangeOfString: @"hello" options:0 range:range];
  if(range.location != NSNotFound)
  {
    range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
    count++; 
  }
}

Answer 3

NSRegularExpression *aRegex = [[NSRegularExpression alloc] initWithPattern:@"Hello" options:NSRegularExpressionCaseInsensitive error:nil];
NSString *targetString = @"Hello, Albert! Hello, again!";
NSInteger numberOfMatches = [aRegex numberOfMatchesInString:targetString options:0 range:NSMakeRange(0, [targetString length])];
[aRegex release];
NSLog(@"number of matches: %d", numberOfMatches); // 2

您可能需要使用正则表达式进行一些操作。

检测单词出现在字符串中的次数 - iphone xcode objective-c

3 个答案: