熊猫的分类变量

Question

When loading a csv file that looks like this

0 1 male 3 4 5 6
1 0 female 6 7 8 9
.....

is it possible to automatically convert the third column to integers, for example 0 for male and 1 for female?

Answer 1

read_csv accepts an argument named converters . This can be used to apply functions to particular columns as a file is read in. converters should be passed in as a dictionary of the following form:

{column_index: function_to_apply}

You could use this to apply a function to the third column. All you need to do is set the function to get a value from a dictionary d which maps "male" to 0 and "female" to 1 :

>>> d = {"male": 0, "female": 1}
>>> pd.read_csv(file.csv, converters={2: d.get})
...
0 1 0 3 4 5 6
1 0 1 6 7 8 9
...