Reverse NSString text
I have been googling so much on how to do this, but how would I reverse a NSString? Ex:hi would become: ih
I am looking for the easiest way to do this.
Thanks!
@Vince I made this method:
- (IBAction)doneKeyboard {
// first retrieve the text of textField1
NSString *myString = field1.text;
NSMutableString *reversedString = [NSMutableString string];
NSUInteger charIndex = 0;
while(myString && charIndex < [myString length]) {
NSRange subStrRange = NSMakeRange(charIndex, 1);
[reversedString appendString:[myString substringWithRange:subStrRange]];
charIndex++;
}
// reversedString is reversed, or empty if myString was nil
field2.text = reversedString;
}
I hooked up that method to textfield1's didendonexit. When I click the done button, it doesn't reverse the text, the UILabel just shows the UITextField's text that I entered. What is wrong?
Block version.
NSString *myString = @"abcdefghijklmnopqrstuvwxyz";
NSMutableString *reversedString = [NSMutableString stringWithCapacity:[myString length]];
[myString enumerateSubstringsInRange:NSMakeRange(0,[myString length])
options:(NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences)
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[reversedString appendString:substring];
}];
// reversedString is now zyxwvutsrqponmlkjihgfedcba
Write a simple loop to do that:
// myString is "hi"
NSMutableString *reversedString = [NSMutableString string];
NSInteger charIndex = [myString length];
while (charIndex > 0) {
charIndex--;
NSRange subStrRange = NSMakeRange(charIndex, 1);
[reversedString appendString:[myString substringWithRange:subStrRange]];
}
NSLog(@"%@", reversedString); // outputs "ih"
In your case:
// first retrieve the text of textField1
NSString *myString = textField1.text;
NSMutableString *reversedString = [NSMutableString string];
NSInteger charIndex = [myString length];
while (myString && charIndex > 0) {
charIndex--;
NSRange subStrRange = NSMakeRange(charIndex, 1);
[reversedString appendString:[myString substringWithRange:subStrRange]];
}
// reversedString is reversed, or empty if myString was nil
textField2.text = reversedString;