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copied!<p>You can combine <code>NSCharacterSet</code>s using a union to add more allowable characters: </p> <pre><code> NSMutableCharacterSet *myCharSet = [[NSCharacterSet alphanumericCharacterSet] mutableCopy]; [myCharSet formUnionWithCharacterSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]; </code></pre> <p>Here is the list of available character sets to choose from:</p> <pre><code>controlCharacterSet whitespaceCharacterSet whitespaceAndNewlineCharacterSet decimalDigitCharacterSet letterCharacterSet lowercaseLetterCharacterSet uppercaseLetterCharacterSet nonBaseCharacterSet alphanumericCharacterSet decomposableCharacterSet illegalCharacterSet punctuationCharacterSet capitalizedLetterCharacterSet symbolCharacterSet newlineCharacterSet </code></pre> <p>Also, your code is checking to make sure <strong>any</strong> character is not outside the set; I think your intention is to check that <strong>all</strong> characters are not outside the set. (This only applies when the user enters more than one character at once - think copy and paste).</p> <p>Consider adjusting your loop to look more like this:</p> <pre><code>NSCharacterSet *myCharSet = [NSCharacterSet alphanumericCharacterSet]; for (int i = 0; i < [string length]; i++) { unichar c = [string characterAtIndex:i]; if ([myCharSet characterIsMember:c] == NO) { // add your user alert here return NO; } } </code></pre> <p>This way your loop won't simply exit on the first good character it finds; instead, it will exit on the first bad character.</p>

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