about pandas dataframe reverse column’s data order

Code import pandas as pd import numpy as np df = pd.DataFrame({"K1":[1,2,3],"K2":[4,5,6]}) df["result"] = (df["K1"].shift(1)*df["K2"]).fillna(1)[::-1] #line A print(df["result"]) print((df["K1"].shift(1)*df["K2"]).fillna(1)[::-1]) #line B print((df["K1"].shift(1)*df["K2"]).fillna(1)) # line C Output 0 1.0 1 5.0 2 12.0 Name: result, dtype: float64 2 12.0 1 5.0 0 1.0 dtype: float64 0 1.0 1 5.0 2 12.0 dtype: float64 Why column result … Read more

Pandas Randomly Data Choosing

I’m a beginner in Pandas. I have a data file containing 10000 different information of users. This data contain 5 columns and 10000 rows. One of these columns is the district of the users and it divides users according to their living place(It defines just 7 different locations and in each of locations some number of users live). as an example, out of this 10000 users, 300 users live in USA and 250 Live in Canada and..
I want to define a DataFrame which includes five random rows of users with the distinct of: USA,Canada,LA,NY and Japan. Also, the dimensions needs to be 20*5. Can you please help me how to do that?
I know for choosing random I need to use