# how to remove substring/suffix using generator expressions
**URL:** https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701
**Category:** Usage
**Created:** [February 25, 2020, 2:31pm UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701 "2020-02-25T14:31:31Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@mmoelle1](https://discourse.cmake.org/u/mmoelle1)
#### Post date: [February 25, 2020, 2:31pm UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/1 "2020-02-25T14:31:31Z")
Assume that I have the expression “/home/user/foo.bar” as the result of a generator-expression and I would like to remove the suffix “.bar”. In practice, the first expression is the full path to an object file and the second is the suffix, that I need to remove in order to obtain the expression “/home/user/foo” which I can then write to file using
file(GENERATE OUTPUT filename CONTENT “$\<…\>”)
Is it possible to remove substrings within generator expressions?
Many thanks in advance and kind regards,
Matthias
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### Author:  [@Gonzalo\_Garramuno](https://discourse.cmake.org/u/Gonzalo_Garramuno)
#### Post date: [February 26, 2020, 2:47am UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/2 "2020-02-26T02:47:45Z")
No. You’ll have to put it in a variable and use STRING( REGEX
REPLACE …) to strip out the .bar extension.
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### Author:  [@mmoelle1](https://discourse.cmake.org/u/mmoelle1)
#### Post date: [February 26, 2020, 5:39am UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/3 "2020-02-26T05:39:31Z")
Thanks! In my understanding, generator expressions are evaluated AFTER the CMakeLists.txt file(s) have been processed. How can I “put” the result of a generator expression into a variable that I can then further process using STRING? Thanks in advance.
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### Author:  [@Gonzalo\_Garramuno](https://discourse.cmake.org/u/Gonzalo_Garramuno)
#### Post date: [February 26, 2020, 11:03am UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/4 "2020-02-26T11:03:14Z")
You are of course correct. Disregard my suggestion. You can
probably use thegenerator expressions to do what you want.
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### Author:  [@Gonzalo\_Garramuno](https://discourse.cmake.org/u/Gonzalo_Garramuno)
#### Post date: [February 26, 2020, 11:05am UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/5 "2020-02-26T11:05:42Z")
TARGET\_FILE\_BASE\_NAME:tgt
or
TARGET\_FILE\_NAME:tgt
The email discourse client swallowed these in the previous answer.
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### Author:  [@mmoelle1](https://discourse.cmake.org/u/mmoelle1)
#### Post date: [February 26, 2020, 11:13am UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/6 "2020-02-26T11:13:23Z")
Thanks but it’s not that easy I guess. I need the base name of a particular object file of a target. It’s the attempt to solve my problem with precompiled headers described in a previous post.
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### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [February 28, 2020, 8:32pm UTC](https://discourse.cmake.org/t/how-to-remove-substring-suffix-using-generator-expressions/701/7 "2020-02-28T20:32:25Z")
I suggested other solutions over there, but I think that more path manipulation/extraction genexes are likely useful anyways. A feature request for them would be useful.