In this article, we will discuss different ways to count True values in a Dataframe Column.
First of all, we will create a Dataframe from a list of tuples i.e.
import pandas as pd import numpy as np # List of Tuples list_of_tuples = [ (False, False, True, False, True, True), (True, False, True, False, True, np.NaN), (False, True, False, False, True, True), (True, True, True, False, True, np.NaN), (True, True, False, True, True, True), (False, False, True, True, True, np.NaN)] # Create a DataFrame object df = pd.DataFrame( list_of_tuples, columns=['A', 'B', 'C', 'D', 'E', 'F']) print(df)
Output
A B C D E F 0 False False True False True True 1 True False True False True NaN 2 False True False False True True 3 True True True False True NaN 4 True True False True True True 5 False False True True True NaN
This Dataframe contains either boolean values or NaN values, and it has six columns. Now let’s see how to get the count of True values in any column of this Dataframe.
Count True values in a Dataframe Column using Series.sum()
Select the Dataframe column using the column name and subscript operator i.e. df[‘C’]. It returns the column ‘C’ as a Series object of only bool values. After that, call the sum() function on this boolean Series object, and it will return the count of only True values in the Series/column.
Let’s understand with an example, where we will get the count of True values in column C,
# Get count of True values in column 'C' count = df['C'].sum() print('Count of True values in Column C : ', count) # Get count of True values in column 'F' count = df['F'].sum() print('Count of True values in Column F : ', count)
Output:
Count of True values in Column C : 4 Count of True values in Column F : 3
Columns ‘C’ & ‘F’ had 4 and 3 True values respectively. We can achieve the same thing using another technique too. Let’s see that in practice,
Count True values in a Dataframe Column using numpy.count_nonzero()
Select the Dataframe column by its name, i.e., df[‘D’]. It returns the column ‘D’ as a Series object of only bool values. Then pass the bool Series object to NumPy’s count_nonzero() function, and it will return the count of only True values in the Series/column.
Let’s understand with an example, where we will get the count of True values in column ‘D’,
# Get count of True values in column 'D' count = np.count_nonzero(df['D']) print('Count of True values in Column D : ', count)
Output:
Count of True values in Column D : 2
Count True values in a Dataframe Column using Series.value_counts()
Select the Dataframe column by its name, i.e., df[‘D’]. It returns the column ‘D’ as a Series object of only bool values. then call the value_counts() function on this Series object. It will return the occurrence count of each value in the series/column. Then fetch the occurrence count of value True. For example,
# Get count of True values in column 'D' count = df['D'].value_counts()[True] print('Count of True values in Column D : ', count)
Output:
Count of True values in Column D : 2
It returned the count of True values in column ‘D’ of the Dataframe.
The complete example is as follow,
import pandas as pd import numpy as np # List of Tuples list_of_tuples = [ (False, False, True, False, True, True), (True, False, True, False, True, np.NaN), (False, True, False, False, True, True), (True, True, True, False, True, np.NaN), (True, True, False, True, True, True), (False, False, True, True, True, np.NaN)] # Create a DataFrame object df = pd.DataFrame( list_of_tuples, columns=['A', 'B', 'C', 'D', 'E', 'F']) print(df) ## Technique 1 ## # Get count of True values in column 'C' count = df['C'].sum() print('Count of True values in Column C : ', count) # Get count of True values in column 'F' count = df['F'].sum() print('Count of True values in Column F : ', count) ## Technique 2 ## # Get count of True values in column 'D' count = np.count_nonzero(df['D']) print('Count of True values in Column D : ', count) ## Technique 3 ## # Get count of True values in column 'D' count = df['D'].value_counts()[True] print('Count of True values in Column D : ', count)
Output:
A B C D E F 0 False False True False True True 1 True False True False True NaN 2 False True False False True True 3 True True True False True NaN 4 True True False True True True 5 False False True True True NaN Count of True values in Column C : 4 Count of True values in Column F : 3 Count of True values in Column D : 2 Count of True values in Column D : 2
Summary:
We learned three different ways to count only True values in any Dataframe column in Pandas.
Pandas Tutorials Learn Data Analysis with Python

Pandas Tutorial Part #1  Introduction to Data Analysis with Python

Pandas Tutorial Part #2  Basics of Pandas Series

Pandas Tutorial Part #3  Get & Set Series values

Pandas Tutorial Part #4  Attributes & methods of Pandas Series

Pandas Tutorial Part #5  Add or Remove Pandas Series elements

Pandas Tutorial Part #6  Introduction to DataFrame

Pandas Tutorial Part #7  DataFrame.loc[]  Select Rows / Columns by Indexing

Pandas Tutorial Part #8  DataFrame.iloc[]  Select Rows / Columns by Label Names

Pandas Tutorial Part #9  Filter DataFrame Rows

Pandas Tutorial Part #10  Add/Remove DataFrame Rows & Columns

Pandas Tutorial Part #11  DataFrame attributes & methods

Pandas Tutorial Part #12  Handling Missing Data or NaN values

Pandas Tutorial Part #13  Iterate over Rows & Columns of DataFrame

Pandas Tutorial Part #14  Sorting DataFrame by Rows or Columns

Pandas Tutorial Part #15  Merging or Concatenating DataFrames

Pandas Tutorial Part #16  DataFrame GroupBy explained with examples
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