在Python 3.4

Question

我有一个简单的问题，但我无法找到合适的解决方案。

我有一个包含学生的csv文件＆＃39;他们注册的名称和科目： 名，subject1，subject2，subject3 Student1，MN1，MN2，MN3 STUDENT2，BN1，BN2，BN3 学生三，MN4，MN5，MN6

学生需要输入他的姓名和科目名称，以检查他是否已注册该科目

我的代码：

import csv

Name = input("Please provide your name: ")
Subject = input("Please provide your Subject: ")

with open('students.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in reader:
        if (row['name'] == Name and row['subject1'] == Subject or 
row['subject2'] == Subject or row['subject3'] == Subject):
            print ("You are registered. It won't take long to run your VM")
        else:
            print ("You are not registered")

我的问题是它给了我多个输出 输出： 请提供您的姓名：Student3 请提供您的主题：MN4 您还没有注册 您还没有注册 你已经注册了。它不会花费很长时间来运行您的VM

显然，应该只是： 你已经注册了。它不会花费很长时间来运行您的VM

你能帮我解决这个问题吗？ 谢谢

Answer 1

请注意，Python中的for循环有一个可选的else子句，当循环结束而没有break语句时将执行该子句...

您的代码打印循环的每次迭代。你想要的只是在循环结束时打印...

with open('students.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in reader:
        if (row['name'] == Name and (row['subject1'] == Subject or row['subject2'] == Subject or row['subject3'] == Subject)):
            print("You are registered. It won't take long to run your VM")
            break
    else:
        print("You are not registered")

Answer 2

数据帧将是存储csv文件的良好结构。请仔细阅读here，无论如何都会进入您的代码。请参考以下代码。

请为此安装pandas和numpy

pip install pandas
pip install numpy

<强>代码：

import pandas as pd
import numpy as np

df = pd.read_csv("testing.csv")

Name = input("Please provide your name: ")
Subject = input("Please provide your Subject: ")

query = '(name == '+ '\'' + Name + '\'' + ') and (subject1 == '+ '\'' \
         + Subject + '\'' + ' or subject2 == ' + '\'' + Subject + '\'' \
         + ' or subject2 == ' + '\'' + Subject + '\')'

if df.query(query).empty:
    print ("You are registered. It won't take long to run your VM")
else:
    print ("You are not registered")

<强>参考：

1. pandas query

Answer 3

我相信字典最适合你：

import csv

data = {i[0]:i[1:] for i in csv.reader(open('filename.csv'))}

Name = input("Please provide your name: ")
Subject = input("Please provide your Subject: ")

if Subject in data[Name]:
    print("you are registered")
else:
    print("you are not registered")