I try to do label encoding for my cities. However, I want it to label according to which city is more than others. Let's say; Oslo has 500 rows Berlin has 400 rows Napoli has 300 rows in the dataset So label encoding will label those cities according to value counts so; Oslo should be labeled as 0, Berlin should be labeled 1, Napoli should labeled as 2
How I can do that?
CodePudding user response:
Use Series.map
by Series
with indices by Series.value_counts
(sorted values by default):
df = pd.DataFrame({'col': ['Berlin'] * 4 ['Oslo'] * 5 ['Napoli'] * 3})
print (df)
s = df['col'].value_counts()
print (s)
Oslo 5
Berlin 4
Napoli 3
Name: col, dtype: int64
s1 = pd.Series(range(len(s)), index=s.index)
print (s1)
Oslo 0
Berlin 1
Napoli 2
dtype: int64
df['newcol'] = df['col'].map(s1)
print (df)
col newcol
0 Berlin 1
1 Berlin 1
2 Berlin 1
3 Berlin 1
4 Oslo 0
5 Oslo 0
6 Oslo 0
7 Oslo 0
8 Oslo 0
9 Napoli 2
10 Napoli 2
11 Napoli 2
Or use dictionary with enumerate
:
s = df['col'].value_counts()
d = {v: k for k, v in enumerate(s.index)}
print (d)
{'Oslo': 0, 'Berlin': 1, 'Napoli': 2}
df['newcol'] = df['col'].map(d)
print (df)
col newcol
0 Berlin 1
1 Berlin 1
2 Berlin 1
3 Berlin 1
4 Oslo 0
5 Oslo 0
6 Oslo 0
7 Oslo 0
8 Oslo 0
9 Napoli 2
10 Napoli 2
11 Napoli 2