pandas數據清洗實現刪除的項目實踐

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準備工作（導入庫、導入數據）

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
import seaborn as  sns
sns.set_style("darkgrid")   
list_csv = ['Amazon_top_selling_book.csv','breast_cancer_wisconsin.csv','diamonds.csv','insurance.csv','netflix_titles.csv','penguins.csv',
           'titanic.csv','winequality-red.csv']
dic_path = r'C:\Users\pandas\Desktop\task\228datasets\datasets'
part_data = pd.read_csv(dic_path+'\\'+list_csv[4])
part_data
  show_id type title director cast country date_added release_year rating duration listed_in description
0 s1 Movie Dick Johnson Is Dead Kirsten Johnson NaN United States September 25, 2021 2020 PG-13 90 min Documentaries As her father nears the end of his life, filmm…
1 s2 TV Show Blood & Water NaN Ama Qamata,
Khosi Ngema,
Gail Mabalane,
Thaban…		 South Africa September 24, 2021 2021 TV-MA 2 Seasons International TV Shows,
TV Dramas,
TV Mysteries		 After crossing paths at a party, a Cape Town t…
2 s3 TV Show Ganglands Julien Leclercq Sami Bouajila,
Tracy Gotoas,
Samuel Jouy,
Nabi…		 NaN September 24, 2021 2021 TV-MA 1 Season Crime TV Shows,
International TV Shows,
TV Act…		 To protect his family from a powerful drug lor…
3 s4 TV Show Jailbirds New Orleans NaN NaN NaN September 24, 2021 2021 TV-MA 1 Season Docuseries, Reality TV Feuds, flirtations and toilet talk go down amo…
4 s5 TV Show Kota Factory NaN Mayur More,
Jitendra Kumar,
Ranjan Raj,
Alam K…		 India September 24, 2021 2021 TV-MA 2 Seasons International TV Shows,
Romantic TV Shows,
TV …		 In a city of coaching centers known to train I…
… … … … … … … … … … … … …

8807 rows × 12 columns

檢測數據情況

Hint:該函數用於檢測任意DataFrame中缺失值情況

def missing_values_table(df):
        mis_val = df.isnull().sum()
        mis_val_percent = 100 * df.isnull().sum() / len(df)
        mis_val_table = pd.concat([mis_val, mis_val_percent], axis=1)
        mis_val_table_ren_columns = mis_val_table.rename(
        columns = {0 : 'Missing Values', 1 : '% of Total Values'})
        mis_val_table_ren_columns = mis_val_table_ren_columns[
            mis_val_table_ren_columns.iloc[:,1] != 0].sort_values(
        '% of Total Values', ascending=False).round(1)
        print ("Your selected dataframe has " + str(df.shape[1]) + " columns.\n"      
            "There are " + str(mis_val_table_ren_columns.shape[0]) +
              " columns that have missing values.")
        return mis_val_table_ren_columns

missing_values_table(part_data)

Your selected dataframe has 12 columns.
There are 6 columns that have missing values.

  Missing Values % of Total Values
director 2634 29.9
country 831 9.4
cast 825 9.4
date_added 10 0.1
rating 4 0.0
duration 3 0.0

DataFrame.drop(labels=None,axis=0, index=None, columns=None, inplace=False)

參數說明：

  • labels 就是要刪除的行列的名字，用列表給定
  • axis 默認為0，指刪除行，因此刪除columns時要指定axis=1；
  • index 直接指定要刪除的行
  • columns 直接指定要刪除的列
  • inplace=False，默認該刪除操作不改變原數據，而是返回一個執行刪除操作後的新dataframe；
  • inplace=True，則會直接在原數據上進行刪除操作，刪除後無法返回。

方式一：刪除指定行或列

labels+axis

demo = part_data.drop(['director'], axis=1)
missing_values_table(demo)

Your selected dataframe has 11 columns.
There are 5 columns that have missing values.

  Missing Values % of Total Values
country 831 9.4
cast 825 9.4
date_added 10 0.1
rating 4 0.0
duration 3 0.0

方式二：利用boolean刪除滿足條件元素所在的行

df = df.drop(df[].index)

# 刪除release_year年份在2009年之前的行
demo = part_data.drop(part_data[part_data["release_year"]<2009].index)
demo.shape

(7624, 12)

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