Question

In Objective-C for iOS, how would I remove the last character of a string using a button action?

Answer 1

In your controller class, create an action method you will hook the button up to in Interface Builder. Inside that method you can trim your string like this:

if ([string length] > 0) {
    string = [string substringToIndex:[string length] - 1];
} else {
    //no characters to delete... attempting to do so will result in a crash
}

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If you want a fancy way of doing this in just one line of code you could write it as:

string = [string substringToIndex:string.length-(string.length>0)];

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*Explanation of fancy one-line code snippet:

If there is a character to delete (i.e. the length of the string is greater than 0)

     (string.length>0) returns 1 thus making the code return:

          string = [string substringToIndex:string.length-1];

If there is NOT a character to delete (i.e. the length of the string is NOT greater than 0)

     (string.length>0) returns 0 thus making the code return:

          string = [string substringToIndex:string.length-0];

     Which prevents crashes.