Backlash error. Pandas filter dataframe using dynamic query string.

Question

Hi all, The problem is related to the Python backlash error. I am creating a dynamic query string for filtering in pandas. The code is:

Answer 1

You can write your own helper function (similar to what you're trying now but making use of **kwargs) and use the @varname syntax as the value placeholder.

def my_filter(df, **kwargs):
    qs = ' & '.join('{0} == @{0}'.format(k) for k in kwargs)
    return df.query(qs, local_dict=kwargs)

Then use as follows:

new_df = my_filter(df, wlbWellType='EXPLORATION', otherColumn='SOMETHING')

This method is safer than manually escaping values as the @varname syntax will do that appropriately for you depending on the value's type.