如何检查字符串中的某些字符？

Question

我有一个字符串..

我正在使用该字符串输入用户的一些字符。

现在我想检查该字符串中“a”是否存在？

谁能告诉我该怎么做？

“a”可以位于字符串中的任何位置。

Answer 1

if ([myString rangeOfString:@"a"].location != NSNotFound) {
  // "a" IS in myString
} else {
  // "a" ISN'T in myString
}

if ([myString rangeOfString:@"a"].location != NSNotFound && [myString rangeOfString:@"b"].location != NSNotFound) {
  // "a" AND "b" are BOTH in myString
} else  if ([myString rangeOfString:@"a"].location != NSNotFound) {
  // ONLY "a" is in myString
} else  if ([myString rangeOfString:@"b"].location != NSNotFound) {
  // ONLY "b" is in myString
} else {
  // Neither "a" NOR "b" is in myString
}

Answer 2

- (BOOL)isCharaterExist:(NSString *)sPhrase withSearchChar:(NSString *)sChar {

      NSAssert(sPhrase != nil && sChar != nil, @"sPhrase and sChar should not be nil");

      return ([sPhrase rangeOfString:sChar].length > NSNotFound);
}

注意：未在运行环境中进行测试，因此可能存在拼写错误！