How to convert a column of string to numerical?

Question

I have this pandas dataframe from a query:

|    name    |    event    |
----------------------------
| name_1     | event_1     |
| name_1     | event_2     |
|          


        

Answer 1

You are asking for the pythonic ways , i think in python this way is to use a technic called one-hot encoding this technic is well implemented in libraries likes sklearn and after one hot encoding you will need to group your dataframe by the first column and apply sum function.

here is a code :

import pandas as pd #the useful libraries
import numpy as np
from sklearn.preprocessing import LabelBinarizer #form sklmearn
dataset = pd.DataFrame([['name_1', 'event_1' ], ['name_1', 'event_2'], ['name_2', 'event_1']], columns=['name', 'event'], index=[1, 2, 3])
data = dataset['event'] #just reproduce your dataframe
enc = LabelBinarizer(neg_label=0)
dataset['event_2'] = enc.fit_transform(data)
event_two = dataset['event_2']
dataset['event_1'] = (~event_two.astype(np.bool)).astype(np.int64) #this is a tip to reproduce the event_1 columns
dataset = dataset.groupby('name').sum()
dataset.reset_index(inplace=True)

and the output is :