Renaming Columns

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When we get our data from other sources, we often want to change the columns names. For example, we might want all of the column names to follow variable name rules, so that we can use df.column name (which tab-completes) rather than df['column_name'] (which takes up extra space).

You can change all of the column names at once by setting the .columns property to a different list. This is great when you need to change all of the columns names at once, but be careful! You can easily mislabel columns if you get the ordering wrong.

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You can also rename individual columns by using the .rename method. Pass a dictionary like the one below to the columns keyword argument:

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Using rename with only the colums keyword will create a new DataFrame, leaving your original DataFrame unchange. That's why we also passed in the keyword argument inplace=True. Using inplace=True lets us edit the original DataFrame.

There are several reasons why .rename is preferable to .columns:

• You can rename just one column
• You can be specific about which column names are getting changed
• If you misspell one of the original column names, this command won't fail. It just won't change anything.