Pandas DataFrame DataFrame.shift() Function

  1. Syntax of pandas.DataFrame.shift():
  2. Example Codes: DataFrame.shift() Function to Shift Along Row
  3. Example Codes: DataFrame.shift() Function to Shift Along Column
  4. Example Codes: DataFrame.shift Method With fill_value Parameter

Pandas DataFrame.shift method is used to shift the index of DataFrame by a specified number of periods with an optional time frequency.

Syntax of pandas.DataFrame.shift():

 DataFrame.shift(periods=1, 
                 freq=None, 
                 axis=0, 
                 fill_value=None)

Parameters

periods Integer. Decides number of periods to shift the index which can be negative or positive
freq DateOffset, tseries.offsets, timedelta, or str. Optional parameter used to shift index values without realigning the data
axis shift along the row (axis=0) or column (axis=1)
fill_value scalar value to be used for newly introduced missing values.

Return

It returns a DataFrame object with shifted index values.

Example Codes: DataFrame.shift() Function to Shift Along Row

import pandas as pd

df = pd.DataFrame({'X': [1, 2, 3,],
                   'Y': [4, 1, 8]})
print("Original DataFrame:")
print(df)

shifted_df=df.shift(periods=1)
print("Shifted DataFrame")
print(shifted_df)

Output:

Original DataFrame:
   X  Y
0  1  4
1  2  1
2  3  8
Shifted DataFrame
     X    Y
0  NaN  NaN
1  1.0  4.0
2  2.0  1.0

Here, we set the value of periods to 1, and this shifts the rows of DataFrame from the top towards the bottom by 1 unit.

While shifting towards the bottom, the topmost rows become vacant and get filled by NaN values by default.

If we want to shift rows from the bottom towards the top, we can set a negative value of the periods parameter.

import pandas as pd

df = pd.DataFrame({'X': [1, 2, 3,],
                   'Y': [4, 1, 8]})
print("Original DataFrame:")
print(df)

shifted_df=df.shift(periods=-2)
print("Shifted DataFrame")
print(shifted_df)

Output:

Original DataFrame:
   X  Y
0  1  4
1  2  1
2  3  8
Shifted DataFrame
     X    Y
0  3.0  8.0
1  NaN  NaN
2  NaN  NaN

It shifts rows from bottom to top by a period of 2.

Example Codes: DataFrame.shift() Function to Shift Along Column

If we want to shift the column axis, we set axis=1 in shift() method.

import pandas as pd

df = pd.DataFrame({'X': [1, 2, 3,],
                   'Y': [4, 1, 8]})
print("Original DataFrame:")
print(df)
shifted_df=df.shift(periods=1,axis=1)
print("Shifted DataFrame")
print(shifted_df)

Output:

Original DataFrame:
   X  Y
0  1  4
1  2  1
2  3  8
Shifted DataFrame
    X    Y
0 NaN  1.0
1 NaN  2.0
2 NaN  3.0

Here, we set the value of periods to 1, and this shifts the columns of DataFrame from the left towards the right by 1 unit.

If we want to shift the column axis from right towards the left, we set a negative value for the periods parameter.

import pandas as pd

df = pd.DataFrame({'X': [1, 2, 3,],
                   'Y': [4, 1, 8]})
print("Original DataFrame:")
print(df)

shifted_df=df.shift(periods=-1,axis=1)
print("Shifted DataFrame")
print(shifted_df)

Output:

Original DataFrame:
   X  Y
0  1  4
1  2  1
2  3  8
Shifted DataFrame
     X   Y
0  4.0 NaN
1  1.0 NaN
2  8.0 NaN

It shifts columns from right to left by the period of 1.

Example Codes: DataFrame.shift Method With fill_value Parameter

In the previous examples, the missing values after shifting are filled with NaN by default. We can also fill the missing values with other values rather than NaN by using the fill_value parameter.

import pandas as pd

df = pd.DataFrame({'X': [1, 2, 3,],
                   'Y': [4, 1, 8]})
print("Original DataFrame:")
print(df)

shifted_df=df.shift(periods=-1,
                    axis=1,
                    fill_value=4)
print("Shifted DataFrame")
print(shifted_df)

Output:

Original DataFrame:
   X  Y
0  1  4
1  2  1
2  3  8
Shifted DataFrame
   X  Y
0  4  4
1  1  4
2  8  4

It fills all the missing values created by the shift() method with 4.

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