How every group of N consecutive rows are folded into one, and separated by tab?

Question

I am trying to solve one competitive question, where I'm stuck at below scenario can some one help me out to understand how the output can be achieved

Explanation : Every group of three consecutive rows should be folded into one

[ Output is shared below ]

Data in file :

Abc 123,
zyxhj pqr
raj
ram:
vilas, 
1234
jkal
yui
gshj

Output :

Abc 123,zyxhj pqr raj
ram:vilas,1234
jkal yui gshj

Please search around or show your efforts when trying to solve your problem. In the output, some lines are joined with spaces, some others are not. Why? — Quasímodo, Nov 01 '20 at 14:33
How to process a multi column text file to get another multi column text file? not exact duplicate, but portion of the answers can be used here: — Sundeep, Nov 01 '20 at 14:49
The last group may be incomplete -- one or two lines? I would expect xargs and paste to correctly terminate the short output line, and awk to leave it without a newline (it would need an END block for that case). — Paul_Pedant, Nov 01 '20 at 15:53

αғsнιη · Accepted Answer · 2020-11-01T20:47:58.360

2

Using xargs:

xargs -d'\n' -n3 <infile

read and print every 3 lines according to the \newline as delimiter

Using paste:

paste -d ' ' - - - <infile

paste data in 3 columns with space delimiter

Using awk:

awk '{ printf "%s%s", $0, (NR%3?OFS:ORS) }' infile

printf every line and then print OFS (Output Field Separator; space by default) if NR (Number of Record) was not module of 3 else ORS (Output Record Separator; newline by default) if it was.

edited Nov 01 '20 at 20:47

answered Nov 01 '20 at 10:36

αғsнιη

41,407

Oh indeed, last 3 lines don't match the behaviour of previous – A.B Nov 01 '20 at 13:06
@αғsнιη I used paste -d - - - this as work for me – codeholic24 Nov 01 '20 at 14:17
1

Also, as you already do the good conditional, you could do this alternative: awk '{ORS = (NR%3 ? OFS : "\n") }1' file (which allows someone to forget printf secret issues temporarily) – thanasisp Nov 01 '20 at 21:05
@thanasisp that's also nice! – αғsнιη Nov 01 '20 at 21:13

How every group of N consecutive rows are folded into one, and separated by tab?

1 Answers1