如何使用Perl将列从多个文件复制到同一输出文件

Question

This is my problem.

I need to copy 2 columns each from 7 different files to the same output file. All input and output files are CSV files. And I need to add each new pair of columns beside the columns that have already been copied, so that at the end the output file has 14 columns.

I believe I cannot use

open(FILEHANDLE,">>file.csv").

Also all 7 CSV files have nearlly 20,000 rows each, therefore I'm reading and writing the files line by line.

It would be a great help if you could give me an idea as to what I should do.

Thanx a lot in advance.

Answer 1

Provided that your lines are 1:1 (Meaning you're combining data from line 1 of File_1, File_2, etc):

• open all 7 files for input
• open output file
• read line of data from all input files
• write line of combined data to output file

Answer 2

Text::CSV is probably the way to access CSV files.

You could define a csv handler for each file (including output), use getline or getline_hr (returns hashref) methods to fetch data, combine it into arrayrefs, than use print .