Python Pandas Series cummax() Function

Pandas Series cummax() Function:

Cumulative maximum is computed over a DataFrame or Series axis by the Pandas Series cummax() function, which returns a DataFrame or Series of the same size including the cumulative maximum.

Syntax:

Series.cummax(axis=None, skipna=True)

Parameters

axis: This is optional. It indicates 0 or “index”, 1 or “columns.” Cumulative maximums are generated for each column if the value is 0 or ‘index’. Cumulative maximums are generated for each row if 1 or ‘columns’ is selected. 0 is the default.

skipna: This is optional. When determining the result, specify True to exclude NA/null values. True is the default value.

Return Value:

The cumulative maximum of scalar or a Series is returned by the cummax() function.

Python Pandas Series cummax() Function

Example1

Here, the cummax() function returns the cumulative maximum of values in a given series.

Approach:

Import pandas module using the import keyword.
Pass some random list as an argument to the Series() function of the pandas module to create a series.
Store it in a variable.
Print the above-given series.
Apply cummax() function on the given series to get the cumulative maximum values of all the elements of the given series and print the result.
The Exit of the Program.

Below is the implementation:

# Import pandas module using the import keyword.
import pandas as pd
# Pass some random list as an argument to the Series() function
# of the pandas module to create a series.
# Store it in a variable.
gvn_series = pd.Series([12, 40, 10, 5, 15, 40, 12, 12])
# Print the above given series
print("The given series is:")
print(gvn_series)
print()
# Apply cummax() function on the given series to get the 
# cumulative maximum values of all the elements of the given series
# and print the result.
print("The cumulative maximum values of all the elements of the given series:")
print(gvn_series.cummax())

Output:

The given series is:
0    12
1    40
2    10
3     5
4    15
5    40
6    12
7    12
dtype: int64

The cumulative maximum values of all the elements of the given series:
0    12
1    40
2    40
3    40
4    40
5    40
6    40
7    40
dtype: int64

Example2

Here, the cummax() function is used on a specified series/columns of a DataFrame.

Approach:

Import pandas module using the import keyword.
Pass some random key-value pair(dictionary), index list as arguments to the DataFrame() function of the pandas module to create a dataframe.
Store it in a variable.
Print the given dataframe
Get the cumulative maximum values of the student_marks column of the dataframe using the cummax() function and print the result.
The Exit of the Program.

Below is the implementation:

# Import pandas module using the import keyword.
import pandas as pd
# Pass some random key-value pair(dictionary), index list as arguments to the 
# DataFrame() function of the pandas module to create a dataframe
# Store it in a variable.
data_frme = pd.DataFrame({
  "student_rollno": [1, 2, 3, 4],
  "student_marks": [80, 35, 25, 90]},
  index= ["virat", "nick" , "jessy", "sindhu"]
)
# Print the given dataframe
print("The given Dataframe:")
print(data_frme)
print()

# Get the cumulative maximum values of the student_marks column of the 
# dataframe using the cummax() function and print the result
print("The cumulative maximum values of the student_marks column of the dataframe:")
print(data_frme['student_marks'].cummax())

Output:

The given Dataframe:
        student_rollno  student_marks
virat                1             80
nick                 2             35
jessy                3             25
sindhu               4             90

The cumulative maximum values of the student_marks column of the dataframe:
virat     80
nick      80
jessy     80
sindhu    90
Name: student_marks, dtype: int64

Python Pandas Series cummax() Function

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