awk substitute column value if not equal to either of 2 values

user_10740658 0
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I am working with a TAB separated file, as follows:

+    +    +
-    +    .
+    +    -
+    +    &
+    -    )

I want to replace column $3 with "NA", but only if it is not equal to either "+" or "-".

The file should be changed to look as follows:

+    +    +
-    +    NA
+    +    -
+    +    NA
+    -    NA

I have tried the following, but it does not work.

cat $file |  awk 'FS=OFS="\t"{ if ($3 !="+" && $3 != "-" ); print }'

How can I do the above?

conditional-statements awk regex
2 Answers

You are close. You may use:

awk 'BEGIN{FS=OFS="\t"} $3 !~ /^[-+]$/{$3="NA"} 1' file

+   +   +
-   +   NA
+   +   -
+   +   NA
+   -   NA
user_5482250

with sed it's easier...

$ sed -E 's/[^+-]$/NA/' file

+    +    +
-    +    NA
+    +    -
+    +    NA
+    -    NA
user_14358690
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