Reorders columns in CSV files.
One often has a CSV file with the right data in its rows, but with extra columns or with the columns in the wrong order. This tool creates a new CSV file with the columns you want in the order you want.
If you are on a Mac or Linux machine you already have python installed. (You want Python 2.7.x, not Python 3.x.)
If you are on Windows you'll probably need to download from
http://python.org and install as appropriate. You need to be able to
successfully say python from a command prompt. (The tutorial
installation instructions at
https://docs.python.org/2/tutorial/interpreter.html
show you how to add python to the path environment variable.)
Suppose that you are expecting a CSV file where each row has a person's Name, Age, Height, and HighScore, but someone instead gives you a CSV file with Height, Weight, Name, Age, HighScore, NumberOfPlays, and ShoeSize. Worse yet, suppose that every time they give you this CSV file the order of the columns is scrambled so that you never know whether they'll give you:
Height,Weight,Name,Age,HighScore,NumberOfPlays,ShoeSize
or
Age,Weight,Height,NumberOfPlays,HighScore,ShoeSize,Name
or even
NumberOfPlays,Age,Name,Height,ShoeSize,HighScore,Weight,Address,LikesIceCream
"Ah," you say, "that should never happen. Please fix it." Everyone agrees that you're right, but you keep receiving very slightly out-of-spec CSV files.
"But we always generate consistent CSV files," your supplier says, but they're simply incorrect. (Maybe they should use this script!)
"The spec doesn't allow that," everyone says, but CSV files with extra and out-of-order columns are the only files that ever arrive.
But you can still deal with the problem by fixing the CSV file like this:
./csvcol.py slightlywrong.csv Name,Age,Height,HighScore > right.csvor
python csvcol.py slightlywrong.csv Name,Age,Height,HighScore > right.csvQ: It dumps my csv data to the screen! Can I have it in a file instead?
A: Yes. You need the redirect operator, which is the little greater than sign in the examples above. If you forget that part then the reformatted CSV data will get dumped to your screen instead of into a file.
Q: Can't I just do this from Excel?
A: Yes, but that requires a person---you---to pay attention to and to interact with the computer every time you want to modify a CSV file. Doing a tedious and repetitive thing like this by hand is a waste of your life; you should be interacting with your friends and family instead, or playing outside. Computers should do this work for you! Also, your competitors might have already automated away all their tedious CSV file manipulation (by using a script like this one, maybe), and they'll soon outcompete you in the marketplace which could mean that you have plenty of time to pursue the rest of your life also. So either way, you win.
Q: What if I want to look at a huge CSV file to see what the columns are?
A: You want the head command. On a Mac or Linux machine, try
running head enormous.csv (or even head -n 1 enormous.csv) and
be amazed at how instantaneously you can see what columns are in the
csv file. There's probably a Windows equivalent, but I don't know
what it would be.
MIT --- See LICENSE.