In the previous exercise, we learned how to add columns to a DataFrame.
Often, the column that we want to add is related to existing columns, but requires a calculation more complex than multiplication or addition.
For example, imagine that we have the following table of customers.
It’s a little annoying that the capitalization is different for each row. Perhaps we’d like to make it more consistent by making all of the letters uppercase.
We can use the
apply function to apply a function to every value in a particular column. For example, this code overwrites the existing
'Name' columns by applying the function
upper to every row in
df['Name'] = df.Name.apply(str.upper)
Apply the function
lower to all names in column
df. Assign these new names to a new column of
'Lowercase Name'. The final DataFrame should look like this: