Objective-C - Remove last character from string

Question

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

User · Answer

The documentation is your friend  NSString supports a call substringWithRange that can shorten the string that you have an return the shortened String  You cannot modify an instance of NSString it is immutable  If you have an NSMutableString is has a method called deleteCharactersInRange that can modify the string in place      NSRange r  r location   0  r size    mutable length -1  NSString  shorted    stringValue substringWithRange r

User · Answer

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   gt  0        string    string substringToIndex  string length  - 1     else         no characters to delete    attempting to do so will result in a crash          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 gt 0         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 gt 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 gt 0  returns 0  thus making the code return                      string    string substringToIndex string length-0             Which prevents crashes

User · Answer

The solutions given here actually do not take into account multi-byte Unicode characters   composed characters    and could result in invalid Unicode strings   In fact  the iOS header file which contains the declaration of substringToIndex contains the following comment      Hint  Use with rangeOfComposedCharacterSequencesForRange  to avoid breaking up composed characters   See how to use rangeOfComposedCharacterSequenceAtIndex  to delete the last character correctly

User · Answer

If it s an NSMutableString  which I would recommend since you re changing it dynamically   you can use    myString deleteCharactersInRange NSMakeRange  myRequestString length -1  1

[ios] Objective-C - Remove last character from string

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