Thank you so much, Jim. That’s exactly what I need. Sorry for not providing the
data frame. But you created the correct data structure. Thanks again!
From: jim holtman <jholt...@gmail.com>
Sent: Monday, March 25, 2019 2:07 PM
To: Yuan, Keming (CDC/DDNID/NCIPC/DVP) <v...@cdc.gov>
Cc: R-help@r-project.org
Subject: Re: [R] loop through columns in a data frame
R Notebook
You forgot to provide what your test data looks like. For example, are all the
columns a single letter followed by “_" as the name, or are there longer names?
Are there always matched pairs (‘le’ and ‘me’) or can singles occur?
Hide
library(tidyverse)
# create some data
test <- tibble(a_le = sample(3, 10, TRUE),
a_me = sample(3, 10, TRUE),
b_le = sample(3, 10, TRUE),
b_me = sample(3, 10, TRUE),
long_le = sample(3, 10, TRUE),
long_me = sample(3, 10, TRUE),
short_le = sample(3, 10, TRUE)
)
So get the names of the columns that contain ‘le’ or ‘me’ and group them
together for processing
Hide
col_names <- grep("_(le|me)$", names(test), value = TRUE)
group <- tibble(id = str_remove(col_names, "_.*"), col = col_names)
result <- group %>%
group_by(id) %>%
do(tibble(x = rowSums(test[, .$col] == 1)))
# add new columns back
for (i in split(result, result$id)){
test[, paste0(i$id[1], "_new")] <- as.integer(i$x > 0)
}
test
a_le
<int>
a_me
<int>
b_le
<int>
b_me
<int>
long_le
<int>
long_me
<int>
short_le
<int>
a_new
<int>
b_new
<int>
long_new
<int>
3
1
2
3
1
2
2
1
0
1
2
3
3
2
1
1
1
0
0
1
3
2
3
2
1
3
3
0
0
1
2
3
1
3
3
1
2
0
1
1
1
1
2
1
1
2
2
1
1
1
3
3
3
1
1
1
1
0
1
1
1
2
1
2
2
2
2
1
1
0
1
3
2
3
1
1
3
1
0
1
3
1
1
1
3
3
2
1
1
0
1
1
1
2
3
3
3
1
1
0
1-10 of 10 rows | 1-10 of 11 columns
Jim Holtman
Data Munger Guru
What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.
On Mon, Mar 25, 2019 at 10:08 AM Yuan, Keming (CDC/DDNID/NCIPC/DVP) via R-help
<r-help@r-project.org<mailto:r-help@r-project.org>> wrote:
Hi All,
I have a data frame with variable names like A_le, A_me, B_le, B_me, C_le,
C_me....
if A_le=1 or A_me=1 then I need to create a new column A_new=1. Same operation
to create columns B_new, C_new...
Does anyone know how to use loop (or other methods) to create new columns? In
SAS, I can use array to get it done. But I don't know how to do it in R.
Thanks,
Keming Yuan
CDC
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