Multi tool use

Searching for element in a column by iterating over the column, pandas

In my data frame I need to remove columns that contain a specific character. In order to search for those columns, I am trying to write a for loop in python that iterate over each column and, if find a column with the unwanted character, this column has to be dropped out.
My data frame appears like this and I need to drop col3 and col5 that have 'f' and 't'

col1 col2 col3 col4 col5 col6
1245 pink f Mar f f
245 green f Feb t f
1237 grey t Apr f f
267 black f Sep t f


I am trying to write a script similar to this

for col in df.items():
if df[col] == 'f'
df = df.drop([col], axis=1)


2 Answers
2

With pd.DataFrame.loc and pd.DataFrame.any functions:

pd.DataFrame.loc

pd.DataFrame.any

In [196]: df
Out[196]:
col1 col2 col3 col4 col5
0 1245 pink t Mar f
1 245 green f Feb t
2 1237 grey f Apr f
3 267 black f Sep f
4 111 red t Aug t

In [197]: df.loc[:, ~((df == 'f') | (df == 't')).any(axis=0)]
Out[197]:
col1 col2 col4
0 1245 pink Mar
1 245 green Feb
2 1237 grey Apr
3 267 black Sep
4 111 red Aug


df

col3

col5

f

You can create a boolean mask of the columns which contains only f and then apply the mask to the df:

f

mask = ((df == 'f') | (df=='t')).any(0)
df = df[df.columns[~mask]]


df = df.astype(np.object)

df.info()

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.