使用 Python 对 dataframe 中的特征列表进行分类编码的 For 循环

Question

I am trying to figure out how to write a for loop to perform categorical encoding over a list of features.

df = ['TRY', 'LOC', 'OUTPUT', 'TYPE_A', 'SIGNAL', 'A-B  SPOT']

Currently, this is how I'm going about it, but it seems repetitive.

obj_df["TRY"] = obj_df["TRY"].astype('category')
obj_df["TRY_cat"] = obj_df["TRY"].cat.codes

I tried following examples to write it and tried using a library as well but I think the logic is just off.

Is there a way to even do this based on how I'm going about it currently? Ideally, I would like to put it into a new dataframe as well.

Thanks in advance!

Answer 1

Try this:

import pandas as pd
df = pd.DataFrame({'Color': {0: 'red', 1: 'green', 2: 'yellow', 3: 'navy_blue'},
'Shape': {0: 'square', 1: 'circle', 2: 'triangle', 3: 'cube'},
 'Description': {0: 'happy', 1: 'sad', 2: 'mad', 3: 'disgust'}})
cols = ['Color', 'Shape', 'Description']

df[cols] = df[cols].astype('category')
df[[col + '_cat' for col in cols]] = pd.concat([df[col].cat.codes for col in cols], axis=1)

print(df)
#        Color     Shape Description  Color_cat  Shape_cat  Description_cat
# 0        red    square       happy          2          2                1
# 1      green    circle         sad          0          0                3
# 2     yellow  triangle         mad          3          3                2
# 3  navy_blue      cube     disgust          1          1                0