https://www.coursera.org/learn/python-data-processing/supplement/qTtOR/3-2-modify-the-dataframes

dataframes.py

Take a look at the DataFrames changes.

Suppose there is a DataFrame here,
>>> aDF
    name    pay
0  Mayue   3000
1  Lilin   4500
2  Wuyun   8000




add columns
Add a tax column into aDF.
>>> aDF['tax'] = [0.05, 0.05, 0.1]
>>> aDF
    name   pay   tax
0  Mayue  3000  0.05
1  Lilin  4500  0.05
2  Wuyun  8000   0.1




2. add rows

We can use loc or iloc to do data selection operation by label or integer index. The append() method and concat() function are also ok.

If we want to add a new row into aDF,
>>> aDF.loc[5] = {'name': 'Liuxi', 'pay': 5000, 'tax': 0.05}
>>> aDF
    name   pay   tax
0  Mayue  3000  0.05
1  Lilin  4500  0.05
2  Wuyun  8000   0.1
5  Liuxi  5000  0.05




3. delete data

The del operation can actually delete the data. The drop() method is safer than the del operation because it can return a new object instead of changing the original DataFrames.

Drop the row which label is 5,
>>> aDF.drop(5)
    name   pay   tax
0  Mayue  3000  0.05
1  Lilin  4500  0.05
2  Wuyun  8000   0.1




Drop the tax column,
>>> aDF.drop('tax', axis = 1)
    name   pay
0  Mayue  3000
1  Lilin  4500
2  Wuyun  8000
5  Liuxi  5000
>>> aDF
    name   pay   tax
0  Mayue  3000  0.05
1  Lilin  4500  0.05
2  Wuyun  8000   0.1
5  Liuxi  5000  0.05




4. modify

modify the column,
>>> aDF['tax'] = 0.03
>>> aDF
    name   pay   tax
0  Mayue  3000  0.03
1  Lilin  4500  0.03
2  Wuyun  8000  0.03
5  Liuxi  5000  0.03




modify the row,
>>> aDF.loc[5] = ['Liuxi', 9800, 0.05]
    name   pay   tax
0  Mayue  3000  0.03
1  Lilin  4500  0.03
2  Wuyun  8000  0.03
5  Liuxi  9800  0.05