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Working with Missing Data

Screen Link:
https://app.dataquest.io/m/402/working-with-missing-data/10/filling-unknown-values-with-a-placeholder

Can someone help explain why we use mutate_at?

Hi Eric,

I am having a hard time also understanding the use of mutate_at in the code you referenced. I think it is because of the use of the anonymous function. The function(x) is applied on v_col and c_col and it cannot be assigned as a value to the 2 variables/columns. Thus, it makes sense to use mutate_at by passing the columns as vectors. Check whether the documentation may help: https://dplyr.tidyverse.org/reference/mutate_all.html.

Let me know what you think.

Create a data frame containing all of the countries and corresponding regions from the happiness2015, happiness2016, and happiness2017 data frames. This is from the screen 5. I am unable to understand how to do this. Please explain.