unique함수는 중복된 것은 걸러버리고 중복되지 않은 값만 출력합니다.
import numpy as np
import pandas as pd
from pandas import DataFrame, Series
df = pd.read_csv('../data/tips.csv',encoding='utf-8')
print(df.head())
'''
total_bill tip sex smoker day time size
0 16.99 1.01 Female No Sun Dinner 2.0
1 10.34 1.66 Male No Sun Dinner 3.0
2 21.01 3.50 Male No Sun Dinner 3.0
3 23.68 3.31 Male No Sun Dinner 2.0
4 24.59 3.61 Female No Sun Dinner 4.0
'''
print(df['sex'].unique())
'''
['Female' 'Male' nan]
'''