正则表达式：保持同一模式在同一行中多次发现，并通过在前面附加单个模式来替换行

Question

Is it possible with notepad++ (or maybe from linux bash shell) to create multiple lines from a pattern found , as many times as the pattern is found and also append single found pattern in the newly created line?

The multi pattern is val=[0-9]+ The single pattern is id=[a-zA-Z0-9]+

Example:

Input lines:

id=af2477,val=333,val=777
id=af3456,val=222,val=444,val=678
id=af3327,val=3234,val=123,val=701

Output lines:

id=af2477,val=333
id=af2477,val=777
id=af3456,val=222
id=af3456,val=444
id=af3456,val=678
id=af3327,val=3234
id=af3327,val=123
id=af3327,val=701

I have tried with 2 subgroups but it wont work. It will only replace the second group once:

find what: (id=[a-zA-Z0-9]+,)(val=[0-9]+,)* replace: \\n\\1,\\2

UPDATE: Both answers from Toto and Wiktor Stribiżew seem to do the job. Haven't tested them yet. I would still like to see how this can work with the use of Notepad++ (even if multiple steps are needed)

Answer 1

Since you also consider using Linux tools for this, an awk solution looks much more viable:

awk 'BEGIN{FS=OFS=","} /^id=[a-zA-Z0-9]+(,val=[0-9]+)*$/{
    for(i=2; i<=NF; i++) {
        print $1,$i
    }; next;
}{print $0}' file > outfile

See the online demo .

Here, any line that matches ^id=[a-zA-Z0-9]+(,val=[0-9]+)*$ (ie matches the format of the lines you need to expand) is split the way you need with for(i=2; i<=NF; i++) {print $1,$i}; next; for(i=2; i<=NF; i++) {print $1,$i}; next; . Else, the line is written as is ( print $0 ).

The BEGIN{FS=OFS=","} part sets the input and output field separator to a comma.

Answer 2

This perl one-liner does the job (output on STDOUT):

perl -anE '($id,$vals)=/(id=\w+),(.+)$/;say "$id,$_" for split/,/,$vals' file
id=af2477,val=333
id=af2477,val=777
id=af3456,val=222
id=af3456,val=444
id=af3456,val=678
id=af3327,val=3234
id=af3327,val=123
id=af3327,val=701

Explanation:

($id,$vals)=/(id=\w+),(.+)$/;       # explode id and values for each line in input file
say "$id,$_" for split/,/,$vals     # print id and each value

You can redirect the output to another file:

perl -anE '($id,$vals)=/(id=\w+),(.+)$/;say "$id,$_" for split/,/,$vals' file > outputfile

Or do the change in-place:

perl -i -anE '($id,$vals)=/(id=\w+),(.+)$/;say "$id,$_" for split/,/,$vals' file

Answer 3

It is possible, yet very complex to do that with one regular expression for which you are gonna have to use (?R) and conditional statements.

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With multiple steps would be pretty simple. You can for instance do find and replace using the max number of val that you might have in the longest lines, such as, imagine 4 would be the largest number of val , then we'll have four of (,val=[^\\r\\n,]*) in our initial expression:

^(id=[^\r\n,]*)(,val=[^\r\n,]*)(,val=[^\r\n,]*)(,val=[^\r\n,]*)(,val=[^\r\n,]*)$

and replace that with four lines,

$1$2\n$1$3\n$1$4\n$1$5
 ---- ---- ---- ----

Demo for Step 1

For any additional step, we can simply remove one val and one line from the end of initial expression and replacement. For example, our expression would look like

^(id=[^\r\n,]*)(,val=[^\r\n,]*)(,val=[^\r\n,]*)(,val=[^\r\n,]*)$

in the second step, for which we'd replace it with:

$1$2\n$1$3\n$1$4
----  ----  ----

Demo for Step 2

In the third and final step, our expression has two vals,

^(id=[^\r\n,]*)(,val=[^\r\n,]*)(,val=[^\r\n,]*)$

and our replacement will have two lines:

$1$2\n$1$3
----  ----

Demo for Step 3

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For the case exampled in the question, only two steps are required and the second and third expressions would likely work just fine.