Question

I have 2 excel files: IDList.csv and Database.csv. IDList contains a list of 300 ID numbers that I want to filter out of the Database, which contains 2000 entries (leaving 1700 entries in the Database).

I tried writing a for loop (For each ID in the IDList, filter out that ID in Database.csv) but am having some troubles with the filter function. I am using Pyvot (http://packages.python.org/Pyvot/tutorial.html). I get a syntax error…Python/Pyvot doesn’t like my syntax for xl.filter, but I can’t figure out how to correct the syntax. This is what the documentation says:

xl.tools.filter(func, range)
Filters rows or columns by applying func to the given range. func is called for each value in the range. If it returns False, the corresponding row / column is hidden. Otherwise, the row / column is made visible.

range must be a row or column vector. If it is a row vector, columns are hidden, and vice versa.

Note that, to unhide rows / columns, range must include hidden cells. For example, to unhide a range:
xl.filter(lambda v: True, some_vector.including_hidden)

And here’s my code:

import xl 

IDList = xl.Workbook("IDList.xls").get("A1:A200").get() 

for i in range(1,301):
     xl.filter(!=IDList[i-1],"A1:A2000")

How can I filter a column in Database.csv using criteria in IDList.csv? I am open to solutions in Python or an Excel VBA macro, although I prefer Python.

Answer 1

import csv

with open("IDList.csv","rb") as inf:
    incsv = csv.reader(inf)
    not_wanted = set(row[0] for row in incsv)

with open("Database.csv","rb") as inf, open("FilteredDatabase.csv","wb") as outf:
    incsv = csv.reader(inf)
    outcsv = csv.writer(outf)
    outcsv.writerows(row for row in incsv if row[0] not in not_wanted)