How to use Awk to create a new field but retain the original field?

问题

Can this be done in Awk?

FILE_IN (Input file)

ID_Number|Title|Name
65765765|The Cat Sat on the Mat|Dennis Smith
65765799|The Dog Sat on the Catshelf|David Jones
65765797|The Horse Sat on the Sofa|Jeff Jones

FILE_OUT (Desired Results)

ID_Number|Title|Nickname|Name
65765765|The Cat Sat on the Mat|Cat Sat|Dennis Smith
65765799|The Dog Sat on the Catshelf|Dog|David Jones
65765797|The Horse Sat on the Sofa||Jeff Jones

Logic to apply:

IF Title contains “ Cat Sat ” OR " cat sat " THEN Nickname = “Cat Sat” #same titlecase/text as was found#
IF Title contains “ Dog ” OR " dog " THEN Nickname = “Dog”

Also, is this task possible with Sed?

回答1:

another awk

$ awk 'BEGIN{FS=OFS="|"} 
            {delete a; 
             match($2,"([Cc]at [Ss]at|[Dd]og)",a); 
             $NF=(NR==1?"Nickname":a[1]) OFS $NF}1' file

ID_Number|Title|Nickname|Name
65765765|The Cat Sat on the Mat|Cat Sat|Dennis Smith
65765799|The Dog Sat on the Catshelf|Dog|David Jones
65765797|The Horse Sat on the Sofa||Jeff Jones

回答2:

This might work for you (GNU sed):

sed -i '1s/|/&Nickname&/2;1b;s/|.*\b\(Cat\|Dog\)\b.*|/&\u\1|/I;t;s/|.*|/&|/' file

Insert the column Nickname into the headings. If the second column contains either the word Cat or Dog insert a third column with the matching word in it. Otherwise insert a blank third column.

回答3:

You could try this with GNU awk:

awk -F"|" -v OFS="|" 'NR==1{$2 = $2 OFS "Nickname"} 
NR>1{if($0 ~ /\s*[Cc]at [Ss]at\s+/) n="Cat"; else if($0 ~ /\s*[dD]og\s+/)n="Dog";
else n=""; $2 = $2 OFS n}  1' file

-F "|" OFS="|" to specify delimiter input and output respectively.
NR==1 To handle header case.
NR>1 To handle data case.

With the same logic, you could use this more compacted code:

awk -F"|" -v OFS="|" 'NR==1{$2 = $2 OFS "Nickname"} 
NR>1{n=($0 ~ /\s*[Cc]at [Ss]at\s+/) ? "Cat" : ($0 ~ /\s*[dD]og\s+/) ? "Dog" : ""; $2 = $2 OFS n}  1' file

来源：https://stackoverflow.com/questions/51730561/how-to-use-awk-to-create-a-new-field-but-retain-the-original-field

标签

awk

sed