Ah! Excellent, jemswira!! Here's what's happening... The regex trys to capture everything past " | " for use as a value. However, in the lines above, there are no values, so $2 is not initialized for those lines which creates errors. To fix this, change the grep to:
You'll notice that the first part of the grep's regex is used in the map statement. The above adds \S+, which means that there need to be non-whitespace characters (i.e., values) beyond " | " for the line to pass. I'm assuming, here, that we can safely ignore lines that don't have anything past " | ". If this is the case, the above grep should resolve the errors.