Python pandas columns index

Pandas – Get Column Index For Column Name

You can get the column index from the column name in Pandas using DataFrame.columns.get_loc() method. DataFrame.columns return all column labels of DataFrame as an Index and get_loc() is a method of Index that gives you a column Index for a given column. In this article, I will explain different ways to get an index from column names with examples.

1. Quick Examples of Column Index From Column Name

If you are in a hurry, below are some quick examples of how to get the column index from the column name in pandas DataFrame.

 # Get column index from column name i.e column 3. idx=df.columns.get_loc("Duration") print("Column Index : "+ str(idx)) # Dictionary of Column name with associated index. idx_dic = <> for col in df.columns: idx_dic[col] = df.columns.get_loc(col) print(idx_dic) # Get Index for Multiple Column Labels/Names query_cols=['Fee','Courses'] cols_index = [df.columns.get_loc(col) for col in query_cols] print(cols_index) # Column index from column name using get_indexer(). cols_index = df.columns.get_indexer(query_cols) 

Now, let’s create a Pandas DataFrame with a few duplicate rows on all columns. Our DataFrame contains column names Courses , Fee , Duration , and Discount .

 import pandas as pd technologies = < 'Courses':["Spark","PySpark","Python","pandas"], 'Fee' :[20000,25000,22000,30000], 'Duration':['30days','40days','35days','50days'], 'Discount':[1000,2300,1200,2000] >df = pd.DataFrame(technologies) print(df) 

2. Get Column Index From Column Name by get_loc()

DataFrame.columns return all column labels of DataFrame as an Index and Index.get_loc() returns a column Index for a given column.

Syntax of Index.get_loc()

 # Syntax for index.get_loc method. Index.get_loc(key, method=None, tolerance=None) 

 # Get column index from column name i.e column 3. idx=df.columns.get_loc("Duration") print("Column Index : "+ str(idx)) # Outputs # Column Index : 2 

3. Using Dictionary of Column Name With Associated Index.

You can see if we want to create a dictionary with column name as key and associated index as value by idx_dic[] method. For example-

 # Dictionary of Column name with associated index. idx_dic = <> for col in df.columns: idx_dic[col] = df.columns.get_loc(col) print(idx_dic) 

4. Get Index for Multiple Column Labels/Names

Using the same get_loc() you can get the Index for multiple column labels/names in DataFrame by passing column labels as a list to this method.

 # Get Index for Multiple Column Labels/Names query_cols=['Fee','Courses'] cols_index = [df.columns.get_loc(col) for col in query_cols] print(cols_index) #output: cols_index : [1,0] 

5. Get Column Index From Column Name Using get_indexer()

In this example, we will see how we will get column index from column name using get_indexer() Method.

 # Column index from column name using get_indexer(). cols_index = df.columns.get_indexer(query_cols) # Outputs: [0,1] 

6. Complete Example – Get Column Index From Column Name in Pandas

 import pandas as pd technologies = < 'Courses':["Spark","PySpark","Python","pandas"], 'Fee' :[20000,25000,22000,30000], 'Duration':['30days','40days','35days','50days'], 'Discount':[1000,2300,1200,2000] >df = pd.DataFrame(technologies) print(df) # Get column index from column name i.e column 3. idx=df.columns.get_loc("Duration") print("Column Index : "+ str(idx)) # Dictionary of Column name with associated index. idx_dic = <> for col in df.columns: idx_dic[col] = df.columns.get_loc(col) print(idx_dic) # Get Index for Multiple Column Labels/Names query_cols=['Fee','Courses'] cols_index = [df.columns.get_loc(col) for col in query_cols] print(cols_index) # Column index from column name using get_indexer(). cols_index = df.columns.get_indexer(query_cols) 

Conclusion

In this article, you have learned how to get column Index from a column name by using get_loc() , and get_indexer() . To get the index for multiple column names pass columns as a list to get_loc() method.

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