CODEWITHSUNDEEP
r
Jan Lerch
Jan Lerch

Reputation: 13

How to efficiently merge many columns of an R data.frame?

I'm trying to merge several hundred columns of a dataframe. Currently trying to do this with a for loop, which isn't working.

The columns are numbered 1 : n, lets say 512.

for(i in 1:512) {
    DF[as.numeric(i)] <-paste(DF[as.numeric(i)], DF[as.numeric(i)+1])  
}

(using the "as.numeric(i)" since I was getting errors when trying to select the next column)

EDIT

All the values are strings, with many rows not being filled till the 512 columns. I'm trying to combine all the strings in 1 row into a single string.

Upvotes: 1

Views: 202

Answers (1)

MKR
MKR

Reputation: 20085

You can try apply with paste0 as:

df <- data.frame(id = 1:10, name = rep(c("Test1", "Test2"),5), 
                 value = 101:110, stringsAsFactors = FALSE)

apply(df, 1, paste0, collapse ="")

#Result
# [1] " 1Test1101" " 2Test2102" " 3Test1103" " 4Test2104" " 5Test1105" " 6Test2106"
# [7] " 7Test1107" " 8Test2108" " 9Test1109" "10Test2110"

Upvotes: 1

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