How do you change the index of a column in python?
Set the DataFrame index using existing
columns. Set the DataFrame index (row labels) using one or more existing columns or arrays (of the correct length). The index can replace the existing index or expand on it. This parameter can be either a single column key, a single array of the same length as the calling DataFrame, or a list containing an arbitrary combination of column keys and arrays. Here,
“array” encompasses Delete columns to be used as the new index. Whether to append columns to existing index. Whether to modify the DataFrame rather than creating a new one. Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this method. Changed row labels or None if Examples Set the index to become the ‘month’ column: >>> df.set_index('month') year sale month 1 2012 55 4 2014 40 7 2013 84 10 2014 31 Create a MultiIndex using columns ‘year’ and ‘month’: >>> df.set_index(['year', 'month']) sale year month 2012 1 55 2014 4 40 2013 7 84 2014 10 31 Create a MultiIndex using an Index and a column: >>> df.set_index([pd.Index([1, 2, 3, 4]), 'year']) month sale year 1 2012 1 55 2 2014 4 40 3 2013 7 84 4 2014 10 31 Create a MultiIndex using two Series: >>> s = pd.Series([1, 2, 3, 4]) >>> df.set_index([s, s**2]) month year sale 1 1 1 2012 55 2 4 4 2014 40 3 9 7 2013 84 4 16 10 2014 31 Contents
By default an index is created for DataFrame. But, you can set a specific column of DataFrame as index, if required. To set a column as index for a DataFrame, use You can also setup MultiIndex with multiple columns in the index. In this case, pass the array of column names required for index, to set_index() method. Syntax of set_index()The syntax of set_index() to setup a column as index is
where To setup MultiIndex, use the following syntax.
Run You can pass as many column names as required. Note that Example 1: Set Column as Index in Pandas DataFrameIn this example, we take a DataFrame, and try to set a column as index. Python Program
Run Output The column
Also, observe the output of original dataframe and the output of dataframe with Example 2: Set MultiIndex for Pandas DataFrameIn this example, we will pass multiple column names as an array to set_index() method to setup MultiIndex for the Pandas DataFrame. Python Program
Run Output
SummaryIn this Pandas Tutorial, we learned how to set a specific column of the DataFrame as index. Related Tutorials
How do you modify an index in Python?To change the index values we need to use the set_index method which is available in pandas allows specifying the indexes.. inplace parameter accepts True or False, which specifies that change in index is permanent or temporary.. True indicates that change is Permanent.. False indicates that the change is Temporary.. How do you rename a column index in Python?You can use the rename() method of pandas. DataFrame to change column/index name individually. Specify the original name and the new name in dict like {original name: new name} to columns / index parameter of rename() . columns is for the column name, and index is for the index name.
Can we change index in DataFrame?Pandas DataFrame: set_index() function
The set_index() function is used to set the DataFrame index using existing columns. Set the DataFrame index (row labels) using one or more existing columns or arrays of the correct length. The index can replace the existing index or expand on it.
How do you create an index of a column in a DataFrame in Python?In order to set index to column in pandas DataFrame use reset_index() method. By using this you can also set single, multiple indexes to a column. If you are not aware by default, pandas adds an index to each row of the pandas DataFrame.
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