摘要： 1. The way to create a DataFrame with its own index and certain columns. state_pop = pd.read_csv("state_population.csv") counts = police_killings["sta 阅读全文

摘要： recent_grads["ShareMen"] = recent_grads["Men"]/recent_grads["Total"] # Create a new column named "ShareMen" , the value is column 'Men' dedide "Total" 阅读全文