Find location of an element in Pandas dataframe in Python

In this article, we will see how to find the position of an element in the dataframe using a user-defined function. Let's first Create a simple dataframe with a dictionary of lists.

How to find an element in Pandas Dataframe?

In a Pandas DataFrame, you can find the position of a specific element or check for its existence using various methods. Here are a few common ways. Let's create a dataframe first and see each method one by one.

import pandas as pd

# List of tuples
students = pd.DataFrame([('Ankit', 23, 'Delhi', 'A'),
            ('Swapnil', 22, 'Delhi', 'B'),
            ('Aman', 22, 'Dehradun', 'A'),
            ('Jiten', 22, 'Delhi', 'A'),
            ('Jeet', 21, 'Mumbai', 'B')
            ])
students

Output: 

    0    1    2    3
0    Ankit    23    Delhi    A
1    Swapnil    22    Delhi    B
2    Aman    22    Dehradun    A
3    Jiten    22    Delhi    A
4    Jeet    21    Mumbai    B

Using isin() Method

The isin() method returns a DataFrame of the same shape as the input, with True at positions where the specified element exists.

# Check if 'Jiten' is in the DataFrame
result = students.isin(['Jiten'])
print(result)

Output:

       0      1      2      3
0  False  False  False  False
1  False  False  False  False
2  False  False  False  False
3   True  False  False  False
4  False  False  False  False

Using any() Method

The any() method checks if the specified element exists in any column, returning a Boolean result.

indices[indices] to filter only the columns with True values. The loop then iterates over these columns, and for each column, it finds the row index where the value exists using students[col_index]. eq().idxmax(), where .idxmax(): Finds the index (row index) where the first occurrence of True appears.

indices = (students == 'Jiten').any() #using any to find index positions
indices

Output:

0     True
1    False
2    False
3    False
dtype: bool

Using NumPy's where() Function

Returns indices where a specified condition is met in the DataFrame, useful for finding the position of an element.

indices = np.where(students == 'Jeet')
# Extracting row and column indices
row_indices, col_indices = indices[0], indices[1]
print(row_indices, col_indices)

Output:

[4] [0]

How to find location of multiple elements in the DataFrame

There are several ways to find the location of multiple elements in a DataFrame. Below are three common approaches.

Using isin()

The code snippet creates a list of target students you want to find. It then uses the isin() method on the 0th column to select rows. Finally, it retrieves the index of those rows using the .index attribute.

import pandas as pd
index_list = students[students.isin(['Ankit', 'Swapnil','Delhi'])]
print(index_list)

Output:

         0   1      2    3
0    Ankit NaN  Delhi  NaN
1  Swapnil NaN  Delhi  NaN
2      NaN NaN    NaN  NaN
3      NaN NaN  Delhi  NaN
4      NaN NaN    NaN  NaN

ankthon

Follow

Improve

Article Tags :

• Python
• Python-pandas
• Python pandas-dataFrame

Practice Tags :

• python