利用函数或者映射进行数据转换

from pandas import Series
import pandas as pd
import numpy as np
data=pd.DataFrame({
"food":["bacon",
"pulled pork",
"bacon",
"Pastrami",
"corned beef",
"Bacon",
"pastrami",
"honey ham",
"nova lox"],
"ounces":[4,3,12,6,7.5,8,3,5,6]
})
meat_to_animal={"bacon":"pig",
"pulled pork":"pig",
"pastrami":"cow",
"corned beef":"cow",
"honey ham":"pig",
"nova lox":"salmon"}
data["animal"]=data["food"].map(str.lower).map(meat_to_animal)
#data["animal"]=data["food"].map(lambda x:meat_to_animal[x.lower()])
print(data)