[FIXED] Use variable in Pandas query

Issue

I'm trying to query a Pandas dataframe like this:

inv = pd.read_csv(infile)
inv.columns = ['County', 'Site', 'Role', 'Hostname'] 
clist = inv.County.unique()  # Get list of counties
for county in clist:  # for each county
    csub = inv.query('County == county')  # create a county subset
    # ... do stuff on subset

But I get an error:

pandas.core.computation.ops.UndefinedVariableError: name 'county' is not defined

I'm sure it's a trivial error, but I can't figure it out. How do I pass a variable to the query method?

Solution

According to the documentation, you can reference variables using @:

csub = inv.query('County == @county')

Answered By - Philip Ciunkiewicz