how to find out if csv file fields are tab delimited or comma delimited

Question

how to find out if csv file fields are tab delimited or comma delimited. I need php validation for this. Can anyone plz help. Thanks in advance.

Answer 1

Aside from the trivial answer that c sv files are always comma-separated - it's in the name, I don't think you can come up with any hard rules. Both TSV and CSV files are sufficiently loosely specified that you can come up with files that would be acceptable as either.

A\tB,C
1,2\t3

(Assuming \t == TAB)

How would you decide whether this is TSV or CSV?