Question

In a file (1000 columns, 2000 rows), for each column there is another column next to it. something like:

[,1] [,2] [,3] [,4] [,5] [,6]
3      3    4    4     4     6
6      5    2    2     5     1
9      1    3    5     4     1
2      5    6    4     8     5
6      1    5    2     3     1

I want to remove those values which their corresponding value is 1
the result:

[,1] [,3] [,5] 
3    4     4
6    2     8
2    3
     6
     5

Answer 1

To echo what @shellter said, it’s both helpful and polite to include what you’ve tried in the question.

Here’s a compact way to accomplish this using split and mapply.

d <- read.table(text='3      3    4    4     4     6
6      5    2    2     5     1
9      1    3    5     4     1
2      5    6    4     8     5
6      1    5    2     3     1', header=FALSE)

cols <- split(as.list(d), rep(1:2, length.out=length(d)))
mapply(function(col1, col2) col1[col2 != 1], 
       cols[[1]], cols[[2]], SIMPLIFY=FALSE)

# $V1
# [1] 3 6 2
# 
# $V3
# [1] 4 2 3 6 5
# 
# $V5
# [1] 4 8