使用apply和map在pandas中添加两列的值

你只需要add:

df["coverage"] = df["coverage"].add(df["reports"])
print (df)
            coverage   name  reports  year
Cochice           29  Jason        4  2012
Pima             118  Molly       24  2012
Santa Cruz        88   Tina       31  2013
Maricopa          64   Jake        2  2014
Yuma              73    Amy        3  2014

要么:

df["coverage"] = df["coverage"] + df["reports"]
print (df)
            coverage   name  reports  year
Cochice           29  Jason        4  2012
Pima             118  Molly       24  2012
Santa Cruz        88   Tina       31  2013
Maricopa          64   Jake        2  2014
Yuma              73    Amy        3  2014

您的代码需要axis=1:

def add(one, two):
  return one + two

df["coverage"] = df.apply(lambda x :add(x["coverage"], x["reports"]), axis=1)
print (df)
            coverage   name  reports  year
Cochice           29  Jason        4  2012
Pima             118  Molly       24  2012
Santa Cruz        88   Tina       31  2013
Maricopa          64   Jake        2  2014
Yuma              73    Amy        3  2014