How Can I Convert a Pandas DataFrame Index into a Column?

Extracting Indexes as Columns in Pandas DataFrames

Converting the index of a Pandas DataFrame into a column allows you to access the index as a regular column within the DataFrame. Here are two methods to achieve this:

Method 1: Using the assignment method

df['index1'] = df.index

This code creates a new column named 'index1' in the DataFrame and assigns the DataFrame's index to it.

Method 2: Using the reset_index() method

df = df.reset_index()

The reset_index() method resets the index and creates a new column with the old index values. This method also reindexes the DataFrame from 0 to the last row.

Example:

Consider the following DataFrame:

df = pd.DataFrame({'gi': [384444683, 384444684, 384444686],
                   'ptt_loc': [593, 594, 596]})
print(df)

Output:

   gi  ptt_loc
0  384444683      593
1  384444684      594
2  384444686      596

Using Method 1:

df['index1'] = df.index
print(df)

Output:

   gi  ptt_loc  index1
0  384444683      593       0
1  384444684      594       1
2  384444686      596       2

Using Method 2:

df = df.reset_index()
print(df)

Output:

   index1        gi  ptt_loc
0        0  384444683      593
1        1  384444684      594
2        2  384444686      596

Note: The reset_index() method can also handle multi-index DataFrames. For instance, if your DataFrame has a three-level index, you can convert the first and third levels into columns using:

df = df.reset_index(level=['tick', 'obs'])

The above is the detailed content of How Can I Convert a Pandas DataFrame Index into a Column?. For more information, please follow other related articles on the PHP Chinese website!