python Pandas DataFrame copy(deep=False) vs copy(deep=True) vs '='

*Python Pandas DataFrame* 是一个功能强大的数据结构，用于处理、分析和操作数据。在使用DataFrame时，有几种复制DataFrame的方法。这篇文章将讨论DataFrame的`copy()`方法的两个参数`deep`的不同取值以及使用`=`进行复制的区别。

python
import pandas as pd
data = {'Name': ['John', 'Emma', 'Michael'],
        'Age': [25, 28, 30],
        'Salary': [50000, 60000, 70000]}
df1 = pd.DataFrame(data)
df2 = df1.copy()

python
df2['Age'] = [26, 29, 31]
print(df1)
print(df2)

     Name  Age  Salary
0    John   25   50000
1    Emma   28   60000
2  Michael   30   70000
     Name  Age  Salary
0    John   26   50000
1    Emma   29   60000
2  Michael   31   70000

python
df3 = df1.copy(deep=True)
df3['Salary'] = [55000, 65000, 75000]
print(df1)
print(df3)

     Name  Age  Salary
0    John   25   50000
1    Emma   28   60000
2  Michael   30   70000
     Name  Age  Salary
0    John   25   55000
1    Emma   28   65000
2  Michael   30   75000

python
df4 = df1
df4['Age'] = [26, 29, 31]
print(df1)
print(df4)

     Name  Age  Salary
0    John   26   50000
1    Emma   29   60000
2  Michael   31   70000
     Name  Age  Salary
0    John   26   50000
1    Emma   29   60000
2  Michael   31   70000