In this article we will discuss different ways to count number of all rows in a Dataframe or rows that satisfy a condition.

Let’s create a Dataframe,

# List of Tuples empoyees = [('jack', 34, 'Sydney', 5) , ('Riti', 31, 'Delhi' , 7) , ('Aadi', 16, np.NaN, 11) , ('Mohit', np.NaN,'Delhi' , 15) , ('Veena', 33, 'Delhi' , 4) , ('Shaunak', 35, 'Mumbai', np.NaN ), ('Shaun', 35, 'Colombo', 11) ] # Create a DataFrame object empDfObj = pd.DataFrame(empoyees, columns=['Name', 'Age', 'City', 'Experience'], index=['a', 'b', 'c', 'd', 'e', 'f', 'g'])

Contents of the dataframe **empDfObj **Â are,

Name Age City Experience a jack 34.0 Sydney 5.0 b Riti 31.0 Delhi 7.0 c Aadi 16.0 NaN 11.0 d Mohit NaN Delhi 15.0 e Veena 33.0 Delhi 4.0 f Shaunak 35.0 Mumbai NaN g Shaun 35.0 Colombo 11.0

Now let’s discuss different ways to count rows in this dataframe.

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## Count all rows in a Pandas Dataframe using Dataframe.shape

##### Dataframe.shape

Each Dataframe object has a member variable shape i.e. a tuple that contains dimensions of a dataframe like,

*(Number_of_index, Number_of_columns)*

First element of the tuple returned by **Dataframe.shape** contains the number of items in index in a dataframe i.e. basically the number of rows in the dataframe. Let’s use this to count number of rows in above created dataframe i.e.

# First index of tuple returned by shape contains the number of index/row in dataframe numOfRows = empDfObj.shape[0] print('Number of Rows in dataframe : ' , numOfRows)

Output:

Number of Rows in dataframe : 7

## Count all rows in a Pandas Dataframe using Dataframe.index

##### Dataframe.index

Each Dataframe object has a member variable index that contains a sequence of index or row labels. We can calculate the length of that sequence to find out the number of rows in the dataframe i.e.

# Get row count of dataframe by finding the length of index labels numOfRows = len(empDfObj.index) print('Number of Rows in dataframe : ' , numOfRows)

Output:

Number of Rows in dataframe : 7

## Count rows in a Pandas Dataframe that satisfies a condition using Dataframe.apply()

Using Dataframe.apply() we can apply a function to all the rows of a dataframe to find out if elements of rows satisfies a condition or not.

Based on the result it returns a bool series. By counting the number of True in the returned series we can find out the number of rows in dataframe that satisfies the condition.

Let’s see some examples,

*Example 1:*

**Count the number of rows in a dataframe for which ‘Age’ column contains value more than 30 i.e.**

# Get a bool series representing which row satisfies the condition i.e. True for # row in which value of 'Age' column is more than 30 seriesObj = empDfObj.apply(lambda x: True if x['Age'] > 30 else False , axis=1) # Count number of True in series numOfRows = len(seriesObj[seriesObj == True].index) print('Number of Rows in dataframe in which Age > 30 : ', numOfRows)

Output:

Number of Rows in dataframe in which Age > 30 : 5

*Example 2:*

**Count the number of rows in a dataframe which contains 11 in any column i.e.**

# Count number of rows in a dataframe that contains value 11 in any column seriesObj = empDfObj.apply(lambda x: True if 11 in list(x) else False, axis=1) numOfRows = len(seriesObj[seriesObj == True].index) print('Number of Rows in dataframe which contain 11 in any column : ', numOfRows)

Output:

Number of Rows in dataframe which contain 11 in any column : 2

*Example 3:*

**Count the number of rows in a dataframe which contains NaN in any column i.e.**

# Count number of rows in a dataframe that contains NaN any column seriesObj = empDfObj.apply(lambda x: x.isnull().any(), axis=1) numOfRows = len(seriesObj[seriesObj == True].index) print('Number of Rows in dataframe which contain NaN in any column : ', numOfRows)

Output:

Number of Rows in dataframe which contain NaN in any column : 3

**Complete example is as follows**

import pandas as pd import numpy as np def main(): print('Create a Dataframe') # List of Tuples empoyees = [('jack', 34, 'Sydney', 5) , ('Riti', 31, 'Delhi' , 7) , ('Aadi', 16, np.NaN, 11) , ('Mohit', np.NaN,'Delhi' , 15) , ('Veena', 33, 'Delhi' , 4) , ('Shaunak', 35, 'Mumbai', np.NaN ), ('Shaun', 35, 'Colombo', 11) ] # Create a DataFrame object empDfObj = pd.DataFrame(empoyees, columns=['Name', 'Age', 'City', 'Experience'], index=['a', 'b', 'c', 'd', 'e', 'f', 'g']) print("Contents of the Dataframe : ") print(empDfObj) print('**** Get the row count of a Dataframe using Dataframe.shape') # First index of tuple returned by shape contains the number of index/row in dataframe numOfRows = empDfObj.shape[0] print('Number of Rows in dataframe : ' , numOfRows) print('**** Get the row count of a Dataframe using Dataframe.index') # Get row count of dataframe by finding the length of index labels numOfRows = len(empDfObj.index) print('Number of Rows in dataframe : ' , numOfRows) print('**** Count Number of Rows in dataframe that satisfy a condition ****') # Get a bool series representing which row satisfies the condition i.e. True for # row in which value of 'Age' column is more than 30 seriesObj = empDfObj.apply(lambda x: True if x['Age'] > 30 else False , axis=1) # Count number of True in series numOfRows = len(seriesObj[seriesObj == True].index) print('Number of Rows in dataframe in which Age > 30 : ', numOfRows) print('**** Count Number of Rows in dataframe that contains a value ****') # Count number of rows in a dataframe that contains value 11 in any column seriesObj = empDfObj.apply(lambda x: True if 11 in list(x) else False, axis=1) numOfRows = len(seriesObj[seriesObj == True].index) print('Number of Rows in dataframe which contain 11 in any column : ', numOfRows) print('**** Count Number of Rows in dataframe that contains NaN ****') # Count number of rows in a dataframe that contains NaN any column seriesObj = empDfObj.apply(lambda x: x.isnull().any(), axis=1) numOfRows = len(seriesObj[seriesObj == True].index) print('Number of Rows in dataframe which contain NaN in any column : ', numOfRows) if __name__ == '__main__': main()

**Output**

Create a Dataframe Contents of the Dataframe : Name Age City Experience a jack 34.0 Sydney 5.0 b Riti 31.0 Delhi 7.0 c Aadi 16.0 NaN 11.0 d Mohit NaN Delhi 15.0 e Veena 33.0 Delhi 4.0 f Shaunak 35.0 Mumbai NaN g Shaun 35.0 Colombo 11.0 **** Get the row count of a Dataframe using Dataframe.shape Number of Rows in dataframe : 7 **** Get the row count of a Dataframe using Dataframe.index Number of Rows in dataframe : 7 **** Count Number of Rows in dataframe that satisfy a condition **** Number of Rows in dataframe in which Age > 30 : 5 **** Count Number of Rows in dataframe that contains a value **** Number of Rows in dataframe which contain 11 in any column : 2 **** Count Number of Rows in dataframe that contains NaN **** Number of Rows in dataframe which contain NaN in any column : 3

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Thanks for reading.

tobiashi, thanks, good examples!

In example 1: “Count the number of rows in a dataframe for which â€˜Ageâ€™ column contains value more than 30 i.e.” Is there a way to get the cumulative count for each row?

I have a similar problem where i want to caluclate all “A” in column “Result”. But i wan to know the count for each row, something like this:

Result A_count

C 0

B 0

A 1

B 1

A 2

and so on…

Thanks

Reetu SinghVery useful!