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

pandas.DataFrame.shift()grammar

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

parameter

Return Value

DataFrameIt returns a object with the shifted index values .

Example code: DataFrame.shift()Function moves along the line

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 periodsset the value of to 1, which will DataFramemove the rows of from the top to the bottom 1by units.

As you move toward the bottom, the top row becomes empty and NaNis filled with the default value.

If we want to move the row from the bottom to the top, we can periodsset the parameter to a negative value.

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 moves the rows from bottom to top with a period of 2.

Example code: DataFrame.shift()Function moves along columns

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

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 periodsset the value of to 1, which will DataFrameshift the column axis of from left to right 1by units.

If we want to move the column axis from right to left, we periodsset a negative value for the 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 the column axis from right to left 1by periods.

Example code: DataFrame.shiftmethod with parametersfill_value

In the previous example, the missing values ​​after shifting are filled by default , but we can also fill them with other values ​​instead of NaNby using the parameter . We can also fill the missing values ​​with other values ​​instead of by using the parameter .fill_valueNaNfill_valueNaN

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 shift()missing values ​​created by the method with .4