Pandas数值计算与排序

import pandas as pd food_info = pd.read_csv("D:\\test\\food_info.csv") #此处需要转义 print(food_info.head(2)) NDB_No Shrt_Desc Water_(g) Energ_Kcal Protein_(g) \ 0 1001 BUTTER WITH SALT 15.87 717 0.85 1 1002 BUTTER WHIPPED WITH SALT 15.87 717 0.85 Lipid_Tot_(g) Ash_(g) Carbohydrt_(g) Fiber_TD_(g) Sugar_Tot_(g) \ 0 81.11 2.11 0.06 0.0 0.06 1 81.11 2.11 0.06 0.0 0.06 ... Vit_A_IU Vit_A_RAE Vit_E_(mg) Vit_D_mcg Vit_D_IU \ 0 ... 2499.0 684.0 2.32 1.5 60.0 1 ... 2499.0 684.0 2.32 1.5 60.0 Vit_K_(mcg) FA_Sat_(g) FA_Mono_(g) FA_Poly_(g) Cholestrl_(mg) 0 7.0 51.368 21.021 3.043 215.0 1 7.0 50.489 23.426 3.012 219.0 [2 rows x 36 columns] #需求：将g转化为mg w_g = food_info["Water_(g)"] w_mg = w_g*1000 food_info["Water_(mg)"] = w_mg #在这这个文件里新添加一列 print (w_g.head(3)) print (w_mg.head(3)) print (food_info["Water_(mg)"].head(3)) 0 15.87 1 15.87 2 0.24 Name: Water_(g), dtype: float64 0 15870.0 1 15870.0 2 240.0 Name: Water_(g), dtype: float64 0 15870.0 1 15870.0 2 240.0 Name: Water_(mg), dtype: float64 w_mg = food_info["Water_(g)"]*food_info["Vit_E_(mg)"] print (w_mg.head(3)) 0 36.8184 1 36.8184 2 0.6720 dtype: float64 w_mg = w_mg/w_mg.max() print (w_mg.head(3)) 0 0.1587 1 0.1587 2 0.0024 Name: Water_(g), dtype: float64 test = food_info["FA_Poly_(g)"] print (test.head(3)) food_info.sort_values("FA_Poly_(g)",inplace=True) #按照升序进行排序 test = food_info["FA_Poly_(g)"] print (test.head(3)) 701 22.541 3634 0.090 4492 1.367 Name: FA_Poly_(g), dtype: float64 4348 0.0 4243 0.0 6154 0.0 Name: FA_Poly_(g), dtype: float64 food_info.sort_values("FA_Poly_(g)",inplace=True,ascending=False) #按照降序进行排序 test = food_info["FA_Poly_(g)"] print (test.head(3)) 656 74.623 662 69.900 8431 67.849 Name: FA_Poly_(g), dtype: float64