使用Pandas合并数据集时出现NameError错误的求助

我用Pandas合并两个学生数据集时触发了NameError，提示名称'c'未定义，代码和报错信息如下：

原代码 #

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)

报错信息 #

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

解决方法 #

错误根源是误用了R语言的语法：c(...)是R里创建向量的方式，但Python中没有这个内置函数。Pandas的pd.merge的by参数需要传入Python的列表（用方括号[]包裹）或者元组。

修正后的核心代码行：

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

完整修正代码 #

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:")

# 替换c(...)为Python列表格式
dq = pd.merge(df, ds, by=["school","sex","age","address","famsize","Pstatus","Medu","Fedu","Mjob","Fjob","reason","nursery","internet"])

print(dq)

内容的提问来源于stack exchange，提问作者coder