# How to trim a text box or replace a single letter at a specific index? **URL:** \ **Category:** Questions about Thunkable X\ **Created:** [February 15, 2023, 5:33am UTC](https://community.thunkable.com/t/how-to-trim-a-text-box-or-replace-a-single-letter-at-a-specific-index/2278076 "2023-02-15T05:33:33Z")\ **Posts on this page:** 1\ **Showing post:** 3
**Author:** ![anandavardhana57zwwl](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@anandavardhana57zwwl](https://community.thunkable.com/u/anandavardhana57zwwl)\ **Post date:** [February 15, 2023, 5:43am UTC](https://community.thunkable.com/t/how-to-trim-a-text-box-or-replace-a-single-letter-at-a-specific-index/2278076/3 "2023-02-15T05:43:45Z")
I played with it and it does not work. Infact this is a very good reference > [@Tips for working with text](https://community.thunkable.com/t/tips-for-working-with-text/154482/2): > > Is Empty The is empty block can be used to check whether or not a string, or piece of text, contains and characters. This block returns true if there are no characters in the string and returns false if there is one or more characters in a string. [isEmpty] Example 1 In this example we want to make sure that the user has typed something into Text\_Input1. There are a couple of ways to do this. These blocks do nothing if Text\_Input1 is empty and only greet the user if they have typed in the t… But none could do what I want. Let me reword my questions Given a text string say 2453635656 if I want to remove the digit at index 3 5 and 8 how would I do it? Given a text string say 2453635656 if I want to replace the digit at #3 by 2, the digit at #5 by 1 and the digit at #8 by 4 how would I do it? All I need is some hint or a nudge in the right direction and I will put the effort. Thanks --- _[View the full topic](https://community.thunkable.com/t/how-to-trim-a-text-box-or-replace-a-single-letter-at-a-specific-index/2278076)._