# DataFrames. Cannot change missing values

**URL:** <https://discourse.julialang.org/t/dataframes-cannot-change-missing-values/25922>\
**Category:** New to Julia\
**Created:** [July 2, 2019, 11:47am UTC](https://discourse.julialang.org/t/dataframes-cannot-change-missing-values/25922 "2019-07-02T11:47:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![BMval](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bmval/32/7647_2.png) [@BMval](https://discourse.julialang.org/u/BMval)\
**Post date:** [July 2, 2019, 11:47am UTC](https://discourse.julialang.org/t/dataframes-cannot-change-missing-values/25922/1 "2019-07-02T11:47:08Z")

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Hi.  
Would you help me?  
I have a DataFrame. Add a new column with missing values, but later I can not change the value.

> insert!(df,15,DataFrames.missing,:b)  
> df[1,:b]=2  
> MethodError: Cannot `convert` an object of type Int64 to an object of type Missing

thank you.  
P.S. How to add a column to the end of a dataframe by default.

---

<div class="post-metadata">

**Author:** ![kdyrhage](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kdyrhage/32/2326_2.png) [@kdyrhage](https://discourse.julialang.org/u/kdyrhage)\
**Post date:** [July 2, 2019, 2:23pm UTC](https://discourse.julialang.org/t/dataframes-cannot-change-missing-values/25922/2 "2019-07-02T14:23:30Z")

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```julia
using DataFrames
df = DataFrame(a = 1:3)
df[:b] = missings(Int, 3)
df[1, :b] = 2

```