如何檢查字符串中的某些字符？

Question

我有一個字符串..

我輸入用戶使用該字符串的一些字符。

現在我想檢查那個字符串「a」是否存在？

誰能告訴我該怎麼做？

「a」可以在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：這不是在運行環境中測試，所以錯字錯誤可能是可能的！