下面我有提供给我的代码，以便加入2个数据集.

import pandas as pd
from sklearn.datasets import load_iris
import matplotlib.pyplot as plt

df= pd.read_csv("student/student-por.csv")
ds= pd.read_csv("student/student-mat.csv")

print("before merge")

print(df)
print(ds)

print("After merging:")

dq = pd.merge(df,ds,by=c("school","sex","age","address","famsize","Pstatus","Medu","Fedu","Mjob","Fjob","reason","nursery","internet"))

print(dq)

我得到这个错误：

Traceback (most recent call last):
  File "/Users/PycharmProjects/datamining/main.py", line 15, in <module>
    dq = pd.merge(df, ds,by=c ("school","sex","age","address","famsize","Pstatus","Medu","Fedu","Mjob","Fjob","reason","nursery","internet"))
NameError: name 'c' is not defined

任何帮助都是很好的，我已经尝试了一段时间，我相信'by=c'是问题所在。
谢谢