如何根据R中另一列中的值替换数据框的列中的值？

Question

I have a dataframe containing the safety data for 100 patients. There are different safety factors for each patient with the size of that specific factor.

   v1_d0_urt_redness v1_d0_urt_redness_size v1_d1_urt_redness v1_d1_urt_redness_size ...
P1          1              20             
P2          1              NA
P3          0              NA
.
.
.

Here redness=1 means there was redness and redness=0 means there was no redness, and therefore the redness_size was not reported.
In order to find what proportion of the data is missing I need to code the data as follows: if (the column containing redness=1 & the column containing redness_size=NA) then (the column containing redness_size<-NA) else if (the column containing redness=0 then the column containing redness_size<-0) to have this coded for d0,d1,.. and to repeat this process for the other variables like hardness, swelling and etc. Any ideas how one could implement this in R?

Answer 1

If I understand well what you are trying to do and assuming your dataframe is called df , you can change values of the column redness_size by doing this:

df[df[,endsWith(colnames(df),"_redness")] == 1 & is.na(df[,endsWith(colnames(df),"redness_size")]),endsWith(colnames(df),"redness_size")] <- NA
df[df[,endsWith(colnames(df),"_redness")] == 1, endsWith(colnames(df),"redness_size")] <- 0