How to Search a Value Within a Pandas DataFrame Column?

Objective For ‘Python Pandas Dataframe Search For Value In Column’

This step-by-step recipe will help you perform Python Pandas search for value in a dataframe.

Code Example For Python Dataframe Search for a Value in a Column

When working with a large dataset on any machine learning or data science project, there is a need to search for some values in a feature, and for that values, we need to get the values from other features.  Searching for values within a dataset might sound complicated, but Python Pandas makes it easy.

The Python Pandas Code below does the following:

1. Creates data dictionary and converts it into DataFrame

2. Uses the "where" function to filter out desired data columns. The pandas.DataFrame.where() function is like the if-then idiom, which checks for a condition to return the result accordingly.

Python Pandas Sample Code to Find Value in DataFrame Column

Below is the Python code to find value in column Pandas DataFrame-

Step 1 - Import the library

import pandas as pd

We have only imported the Python Pandas library needed for this code example.

Step 2 - Setting up the Data

We have created a dictionary of data and passed it to pd.DataFrame to make a dataframe with columns 'first_name', 'last_name', 'age', 'Comedy_Score' and 'Rating_Score'.

raw_data = {'first_name': ['Sheldon', 'Raj', 'Leonard', 'Howard', 'Amy'], 'last_name': ['Copper', 'Koothrappali', 'Hofstadter', 'Wolowitz', 'Fowler'], 'age': [42, 38, 36, 41, 35], 'Comedy_Score': [9, 7, 8, 8, 5], 'Rating_Score': [25, 25, 49, 62, 70]} df = pd.DataFrame(raw_data, columns = ['first_name', 'last_name', 'age', 'Comedy_Score', 'Rating_Score']) print(df)

Try A Few More Pandas Code Examples With These Python Pandas Projects with Source Code

Step 3 - Using Python Pandas To Find in DataFrame The Desired Values

We are searching the data in the feature Rating_Score with values less than 50, and for those values, we are selecting the corresponding values in comedy_Score.

print(df['Comedy_Score'].where(df['Rating_Score'] < 50))

The output is as shown below -

 first_name     last_name  age  Comedy_Score  Rating_Score

0    Sheldon        Copper   42             9            25

1        Raj  Koothrappali   38             7            25

2    Leonard    Hofstadter   36             8            49

3     Howard      Wolowitz   41             8            62

4        Amy        Fowler   35             5            70

0    9.0

1    7.0

2    8.0

3    NaN

4    NaN

Name: Comedy_Score, dtype: float64

How To Search in a Pandas DataFrame Column For a Value Using Regular Expressions?

You can use the str.contains() method to perform Python Pandas search in a DataFrame column using regular expressions. For example, to search for all rows where the column name contains the letter ‘J’, you can use the following code-

df = pd.DataFrame({'name': ['John', 'Jane', 'Mike'], 'age': [25, 26, 27]})

filtered_df = df.loc[df['name'].str.contains('J')]

print(filtered_df)

The above code will give you the following output:

 name  age

0  John  25

1  Jane  26