如何使用pandas在python中过滤数据？

Question

I have a list:

list = ['firstname', 'lastname', 'email', 'phonenumber']

I want to iterate for this list as:

import pandas as pd

df = pd.read_csv(filepath)

df[ pd.notnull(df[firstname]) | pd.notnull(df[lastname]) | 
    pd.notnull(df[email]) | pd.notnull(df[phonenumber])]

How do I perform the above process using a loop?

Answer 1

You can filter using columns with null values.

df.isnull().any()
>> 
firstname True
lastname True
...

df.isnull().sum()

It shows all columns and the total NaNs of each column (your list).

Answer 2

First, do not shadow built-in class names:

L = ['firstname', 'lastname', 'email', 'phonenumber']

Then use notnull with any along axis=1 to construct a Boolean series mask:

res = df[df[L].notnull().any(1)]