removing an extra column in vim

So I load a csv in vim, and realize I screwed up. I wrote out 2 probabilities instead of one.

 2 100004,0.732524934269992,0.267475065730008
 3 100015,0.502454568719362,0.497545431280638
 4 100026,0.426691576440626,0.573308423559374
 5 100030,0.796236053493448,0.203763946506552
 6 100047,0.745809954575253,0.254190045424747
 7 100052,0.980561973536192,0.0194380264638075
 8 100056,0.86757763360163,0.13242236639837
 9 100061,0.580641527965135,0.419358472034865
 10 100067,0.487600362330103,0.512399637669897
 11 100068,0.336393531503461,0.663606468496539
 12 100082,0.582289239857109,0.417710760142891
 13 100084,0.234077152161437,0.765922847838563
 14 100097,0.252967375901838,0.747032624098162
 15 100098,0.121602233424238,0.878397766575762

In vim, to get rid of that extra column, you just type:

:1,$s/,[^,]*$//

This says: “from the first line to the last line, swap anything that’s a comma followed by a bunch of not-commas at the end of the line, for nothing. So it just gets rid of the last column. (This will not work for fancy CSVs with quoted strings with embedded commas as the last field. So sad.