Delete rows if there are null values in a specific column in Pandas dataframe [duplicate]

问题

This question already has answers here:

Python: How to drop a row whose particular column is empty/NaN? (2 answers)

How to select rows from a DataFrame based on column values? (10 answers)

Closed 2 years ago.

Am new to python pandas. Need some help with deleting few rows where there are null values. In the screenshot, I need to delete rows where charge_per_line = - using python pandas. Thanks !!

回答1:

If the relevant entries in Charge_Per_Line are empty (NaN) when you read into pandas, you can use df.dropna:

df = df.dropna(axis=0, subset=['Charge_Per_Line'])

If the values are genuinely -, then you can replace them with np.nan and then use df.dropna:

import numpy as np

df['Charge_Per_Line'] = df['Charge_Per_Line'].replace('-', np.nan)
df = df.dropna(axis=0, subset=['Charge_Per_Line'])

回答2:

Multiple ways

1. Use str.contains to find rows containing '-'

   df[~df['Charge_Per_Line'].str.contains('-')]
   

2. Replace '-' by nan and use dropna()

   df.replace('-', np.nan, inplace = True)
   df = df.dropna()
   

来源：https://stackoverflow.com/questions/49291740/delete-rows-if-there-are-null-values-in-a-specific-column-in-pandas-dataframe