How to use the std() function in Pandas

Overview

The std() function in pandas obtains the standard deviation of the values of a specified axis of a given DataFrame.

Mathematically, the standard deviation is defined as measuring the dispersion of each value in a dataset from the mean.

Syntax

The std() function takes the syntax shown below:

DataFrame.std(axis=NoDefault.no_default, skipna=True, numeric_only=None, **kwargs)
Syntax for the std() function in Pandas

Parameter value

The std() function takes the following optional parameter values:

  • axis: This represents the name for the row (designated as 0 or 'index') or the column (designated as 1 or columns) axis.
  • skipna: This takes a Boolean value indicating whether NA or null values are to be excluded.
  • ddof: This takes an int that represents the delta degrees of freedom.
  • numeric_only: This takes a Boolean value indicating whether to include only float, int, or Boolean columns.
  • **kwargs: This is an additional keyword argument that can be passed to the function.

Example

# A code to illustrate the std() function in Pandas
# Importing the pandas library
import pandas as pd
# Creating a DataFrame
df = pd.DataFrame([[1,2,3,4,5],
[1,7,5,9,0.5],
[3,11,13,14,12]],
columns=list('ABCDE'))
# Printing the DataFrame
print(df)
# Obtaining the median value vertically across rows
print(df.std())
# Obtaining the median value horizontally over columns
print(df.std(axis="columns"))

Explanation

  • Line 4: We import the pandas library.
  • Lines 7–10: We create a DataFrame, df.
  • Line 12: We print  df.
  • Line 15: Using the std() function, we obtain the standard deviation of values that run downwards across the rows (axis 0). We print the result to the console.
  • Line 18: Using the std() function, we obtain the standard deviation of values that run horizontally across the columns (axis 1). We print the result to the console.