Text processing : Replacing strings in a line with corresponding strings

Question

I have these as input files

file1

Red + Yellow = Orange; Yellow + Blue = Green; Blue + Red = Violet

file2

Red;1
Yellow;2
Blue;3

I am doing this in unix.

Output

file3

1 + 2 = Orange; 2 + 3 = Green; 3 + 1 = Violet

strings are delimited by semicolon. file1 and file3 are single rows. file2 should looks like this: Red;1 \n Yellow;2 \n Blue;3 \n — peon, Dec 06 '16 at 06:31
Possible duplicates: String replacement using a dictionary or Replace strings in a file based on a list of strings and a list of corresponding replacements — don_crissti, Dec 06 '16 at 11:19

score 1 · Answer 1 · answered Dec 06 '16 at 06:52

1

awk 'NR == FNR { # First file
    split($0,a,/;/)
    #print "change " a[1] "to " a[2]
    change[a[1]]=a[2]
}
NR != FNR {
    for (i=1;i<NF;i++) {
            if ($i in change) {
                    $i=change[$i]
            }
    }
    print
}' file2 file1

Use the awk idiom NR != FNR to tell if this is the first file or the second. If it is the first file then split the line on ; and store the mapping in the change array. If it is the second then loop over the input field, if any match then replace with the correct change. At the end print the result.

answered Dec 06 '16 at 06:52

icarus

17,920

Thank you for that. What if I change my file 2 into something like this? Red;1 2 Yellow;2 3 Blue;3 1
And the output file will look like this 1 2 + 2 3 = Orange; 2 3 + 3 1 = Green; 3 1 + 1 2 = Violet

which is essentially just replacing the strings in file1 with the corresponding string in the 2nd col of file2. Will this still work?
– peon Dec 06 '16 at 07:17
@peon please edit your question to show the data files, and try the commands. If I understand your comment correctly the answer is yes. – icarus Dec 06 '16 at 13:07

score 1 · Answer 2 · answered Dec 06 '16 at 07:56

1

#!/bin/bash

IFS=";"
while read NAME VALUE
do
    sed -i "s/${NAME}/${VALUE}/g" file1
done < file2

answered Dec 06 '16 at 07:56

Kamaraj

4,365

This would also replace the words when they occur as substrings, as in LightBlue. – Kusalananda Apr 20 '19 at 16:08

Text processing : Replacing strings in a line with corresponding strings

2 Answers2