How can pandas modify data in an entire column?

In pandas, you can use df[column] = value to modify the data in an entire column, where df is the data frame, column is the name of the column to be modified, and value is the new value to assign to that column.

Here are some examples of code:

1. Change the entire column to a specific value.

import pandas as pd

# 创建数据框
df = pd.DataFrame({'A': [1, 2, 3],
                   'B': [4, 5, 6]})

# 修改整列'A'的值为10
df['A'] = 10

print(df)

Output:

    A  B
0  10  4
1  10  5
2  10  6

1. Change the values of an entire column to the values of another column.

import pandas as pd

# 创建数据框
df = pd.DataFrame({'A': [1, 2, 3],
                   'B': [4, 5, 6]})

# 修改整列'A'的值为列'B'的值
df['A'] = df['B']

print(df)

Output:

   A  B
0  4  4
1  5  5
2  6  6

1. Change the values of the entire column based on conditions.

import pandas as pd

# 创建数据框
df = pd.DataFrame({'A': [1, 2, 3],
                   'B': [4, 5, 6]})

# 修改整列'A'的值，如果值大于2则赋值为10，否则赋值为0
df.loc[df['A'] > 2, 'A'] = 10
df.loc[df['A'] <= 2, 'A'] = 0

print(df)

Output:

    A  B
0   0  4
1   0  5
2  10  6

These are some basic examples of modifying data in entire columns, which you can customize according to your specific needs.