Pandas Get Column Name by Index or Position

In Pandas, you can get the column name by index or position using the columns attribute or the iloc[] indexer. Sometimes you may have a column index and want to get column name by index in pandas DataFrmae, you can do so by using DataFrame.columns[idx]. Note that the index starts from 0.

Key Points –

• Use df.columns to retrieve a list-like object containing all column names.
• Use df.columns[index] to get the column name at a specific position.
• Negative indices can be used to access columns from the end (e.g., df.columns[-1] for the last column).
• The .iloc[] function can be used to select columns by position, and then retrieve the name using .name.
• Use a list of indices df.columns[list_of_indices] to get multiple column names.

1. Quick Examples of Get Column Name by Index or Position

If you are in a hurry, below are some quick examples of how to get column name by index or position

# Quick examples of get column name by index

# Example 1: Get column name by index 
print(df.columns)

# Example 2: Get column name by index
index_to_get = 2
df2 = df.columns[index_to_get]

# Example 3: Get column name by index 
# Using the columns attribute
df2 = df.columns[2]

# Example 4: Get multiple column names by index
indices_to_get = [1, 3]  
df2 = df.columns[indices_to_get]

# Example 5: Get column name by index 
# Using iloc[]
index_to_get = 2
df2 = df.columns[df.iloc[:, index_to_get].name]

2. Get Column Name by Index Example

DataFrame.columns returns an object of pandas.core.indexes.base.Index and use the position by using [] operator to get the column name by index or position.

Now, Let’s create Pandas DataFrame using data from a Python dictionary, where the columns are Courses, Fee, Duration and Discount

# Create pandas DataFrame 
import pandas as pd
import numpy as np
technologies = {
    'Courses':["Spark","PySpark","Python"],
    'Fee' :[20000,25000,22000],
    'Duration':['30days','40days','35days'],
    'Discount':[1000,2300,1200]
              }
df = pd.DataFrame(technologies)
print("Create DataFrame:\n",df)

Yields below output.

Now let’s get the column names from pandas DataFrame, As I said the below example returns an Index object containing all column names.

# Get column name by index 
print(df.columns)

# Output:
# Index(['Courses', 'Fee', 'Duration', 'Discount'],
# dtype='object')

3. Using Columns Attribute

You can use the columns attribute directly to get the column name by index. For instance, the df.columns returns an Index object containing the column names, and you can access a specific column name by its index using standard list indexing.

# Get column name by index
index_to_get = 2
df2 = df.columns[index_to_get]
print(f"Column name at index {index_to_get}: {df2}")

# Get column name by index 
# Using the columns attribute
df2 = df.columns[2]
print(f"Column name at index {2}: {df2}")

# Output:
# Column name at index 2: Duration

4. Get Multiple Column Names by Index

Similarly, you can get multiple column names by index in Pandas by providing a list of indices. For instance, df.columns[indices_to_get] returns a new Index object containing the column names corresponding to the specified list of indices. Adjust the df2 list based on the indices you want to retrieve.

# Get multiple column names by index
indices_to_get = [1, 3]  # List of indices
df2 = df.columns[indices_to_get]
print(f"Column names at indices {indices_to_get}: {df2}")

# Output:
# Column names at indices [1, 3]: Index(['Fee', 'Discount'], dtype='object') 

5. Using the iloc[] Indexer

You can use the iloc[] indexer to get the column name by index. For example, df.iloc[:, index_to_get].name gives you the column name corresponding to the specified index. The df.iloc[:, index_to_get] part selects the column as a Pandas Series and .name retrieves the column name.

# Get column name by index using iloc[]
index_to_get = 2
df2 = df.columns[df.iloc[:, index_to_get].name]
print(f"Column name at index {index_to_get}: {df2}")

# Output:
# Column name at index 2: Duration

Frequently Asked Questions on Get Column Name by Index or Position

Conclusion

In this article, I have explained you can retrieve the column name by index in a Pandas DataFrame using either the columns attribute or the iloc[] indexer.

Happy Learning !!

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