# Automatic detection of letters in text input

**URL:** <https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617>\
**Category:** Questions about Thunkable X\
**Tags:** beginner\
**Created:** [October 18, 2024, 8:31am UTC](https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617 "2024-10-18T08:31:54Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ant\_1](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/ant_1/32/183393_2.png) [@ant\_1](https://community.thunkable.com/u/ant_1)\
**Post date:** [October 18, 2024, 8:31am UTC](https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617/1 "2024-10-18T08:31:54Z")

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hey guys! hope everyone is doing well.  
in my text input i want to make sure that the only thing the user can input is letters. I know how to do it manually by saying if text input text contain a or text input text contain b, etc. But is there another faster way to do this? Is there a block that say if text input text contains letters?

thanks!

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**Author:** ![tatiang](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/tatiang/32/55482_2.png) [@tatiang](https://community.thunkable.com/u/tatiang)\
**Post date:** [October 18, 2024, 12:25pm UTC](https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617/2 "2024-10-18T12:25:17Z")

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Here’s a better way:

1. Create a variable and set its value to the text string “abcdefg…” (all the letters). If you need to, you can include uppercase letters as well.
2. Loop through each character in the text input’s text. If the variable does not contain the character, then they have entered an invalid input and you can exit the loop.

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<div class="post-metadata">

**Author:** ![ant\_1](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/ant_1/32/183393_2.png) [@ant\_1](https://community.thunkable.com/u/ant_1)\
**Post date:** [October 19, 2024, 4:22am UTC](https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617/3 "2024-10-19T04:22:51Z")

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hi tatiang. thanks for the reply. could you explain to me what you mean by a loop? thanks

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<div class="post-metadata">

**Author:** ![tatiang](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/tatiang/32/55482_2.png) [@tatiang](https://community.thunkable.com/u/tatiang)\
**Post date:** [October 19, 2024, 5:50am UTC](https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617/4 "2024-10-19T05:50:47Z")

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A loop is a standard programming term. In Thunkable, it’s represented by one of these blocks: [Control Blocks | Thunkable Docs](https://docs.thunkable.com/blocks/blocks/control#loops-blocks).

If you Google _loop through word Thunkable_, you’ll find several forum posts that discuss how to do this.

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**Author:** ![system](https://us1.discourse-cdn.com/flex015/uploads/thunkable/original/3X/0/f/0f59f292712368bce16ff80133ae10de8a6f27e8.png) [@system](https://community.thunkable.com/u/system)\
**Post date:** [January 17, 2025, 5:50am UTC](https://community.thunkable.com/t/automatic-detection-of-letters-in-text-input/3280617/5 "2025-01-17T05:50:54Z")

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