# Nan Error in CSV

**URL:** <https://discourse.julialang.org/t/nan-error-in-csv/49197>\
**Category:** New to Julia\
**Tags:** question, function\
**Created:** [October 28, 2020, 6:24pm UTC](https://discourse.julialang.org/t/nan-error-in-csv/49197 "2020-10-28T18:24:20Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![yasser\_rajwani](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/yasser_rajwani/32/14278_2.png) [@yasser\_rajwani](https://discourse.julialang.org/u/yasser_rajwani)\
**Post date:** [October 28, 2020, 6:24pm UTC](https://discourse.julialang.org/t/nan-error-in-csv/49197/1 "2020-10-28T18:24:20Z")

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I have a CSV file which contains about 1500 values some of which are “nan”, I am trying to write a function that would replace the “nan” values with zero.

I tried using the replace\_nan(v) and CSV write function, however have been unsuccesful.

P.S. I am julia beginer, so any help will be appreicated.

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**Author:** ![pdeffebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pdeffebach/32/10320_2.png) [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Post date:** [October 28, 2020, 6:42pm UTC](https://discourse.julialang.org/t/nan-error-in-csv/49197/2 "2020-10-28T18:42:18Z")

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One thing you could do is use `missingstring = "nan"` to read in the NaN values as `missing`, then perform `replace(col, missing => NaN)` on all the columns that should have `NaN` values.

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**Author:** ![heliosdrm](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/heliosdrm/32/3851_2.png) [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Post date:** [October 28, 2020, 10:30pm UTC](https://discourse.julialang.org/t/nan-error-in-csv/49197/3 "2020-10-28T22:30:33Z")

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`replace(x, NaN => 0)`, (or `replace!(x, NaN => 0)` if you want to do in-place replacement) should work in many circumstances. Can you post a minimum reproducible example where that does not work?

Please consider the following recommendations to post your example:

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