CODEWITHSUNDEEP
rloops
Keniajin
Keniajin

Reputation: 1659

looping through variable names according to their prefix in R

I have to carry out a number of comparisons, and I was wondering how to automate the overall procedure. Suppose I have only the following variables:

age location serial weight height age_n location_n serial_n weight_n height_n

I want to compare 

data[weight != weight_n,c("serial ","weight","weight_n") , drop = F]

for each and every variable. How can I loop over all the variables?

I was trying

for (nam in colnames(df)) {
  data['nam' != 'nam'_n,c("serial ",'nam','nam'_n) , drop = F]           
}

Upvotes: 0

Views: 1539

Answers (1)

BrodieG
BrodieG

Reputation: 52687

Here is an alternate. Note you should only loop through the column names w/o the _n (hence the grep in the for section):

for(nam in colnames(df)[-grep("_n$", colnames(df))]) {
  data[
    data[[nam]] != data[[paste0(nam, "_n"]], 
    c("serial", nam, paste0(nam, "_n")
  ]  
}

Upvotes: 3

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