Pandas Passing Variable Names Into Column Name
I have a dataframe that contains 13 different column names, I have separated these headings into two lists. I now want to perform different operations on each of these lists. Is i
Solution 1:
I think you can use subset
created from list
CONT
:
printdf
age fnlwgt capital-gain
0 a 9th 5
1 b 9th 6
2 c 8th 3
CONT = ['age','fnlwgt']
printdf[CONT]
age fnlwgt
0 a 9th
1 b 9th
2 c 8th
printdf[CONT].count()
age 3
fnlwgt 3
dtype: int64
printdf[['capital-gain']]
capital-gain
0 5
1 6
2 3
Maybe better as list
is dictionary
, which is created by to_dict
:
d = df[CONT].count().to_dict()
print d
{'age': 3, 'fnlwgt': 3}
print d['age']
3
print d['fnlwgt']
3
Solution 2:
try:
for column_name, column in df.transpose().iterrows():
if column_name in CONT:
print(df[column_name].count())
else:
print('')
edit:
To answer your question more precisely:
You can use variables to select cols in 2 ways: df[list_of_columns]
will return a DataFrame with the subset of cols in list_of_columns
. df[column_name]
will return the Series for column_name
Solution 3:
The following will print the count of each column in the dataframe if it is a subset of your CONT list.
CONT = ['age', 'fnlwgt', 'capital-gain', 'capital-loss']
df = pd.DataFrame(np.random.rand(5, 2), columns=CONT[:2])
>>> df
age fnlwgt
0 0.079796 0.736956
1 0.120187 0.778335
2 0.698782 0.691850
3 0.421074 0.369500
4 0.125983 0.454247
Select the subset of columns and perform a transform.
>>> df[[c for c in CONT if c in df]].count()
age 5
fnlwgt 5
dtype: int64
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