python - 从 csv 文件导入和导出

Question

所以我正在尝试创建一个可以搜索数据文件的代码：

1. 按姓氏检索和显示联系人的详细信息
2. 按出生日期检索并显示特定月份生日的所有联系人。

这是我创建的代码：

def search():
    option = input('Please select to search by \n1. Surname\n2. D.O.B\n')
    if option == '1':
        surname = input('Please enter surname: ')
        while not surname.isalpha():
            surname = str(input('Please enter a valid surname: '))
        Myfile = open('Address book.csv', 'rt')
        for line in Myfile:
            if ',' + str(surname) + ',' in line:
                print(line)
            else:
                 print('No contacts found')
    elif option == '2':
        Validmonth = False
        while Validmonth == False:
            month = input('Please enter the birth month')
            if month >='13' and month <='0':
                print('Please enter a valid month')
            else:
                Validmonth = True
            Myfile = open ('Address book.csv', 'rt')
            for line in Myfile:
                if str(month) in line:
                    print(line)
                else:
                    print('No contacts found')
    else:
        print('Error, select a valid option')
        search()

search()

当我尝试代码时，我不断得到这个结果：

Please select to search by 
1. Surname
2. D.O.B
1
Please enter surname: Vickers
No contacts found
No contacts found
No contacts found
No contacts found
No contacts found
No contacts found
No contacts found
No contacts found

我想知道为什么？有人请帮忙吗？

Answer 1

您测试每一行的姓氏，然后打印No contacts found每一行不匹配的。

找到名称后跳出循环，并使用该else套件进行for循环：

for line in Myfile:
    if ',' + str(surname) + ',' in line:
        print(line)
        break
else:
    print('No contacts found')

elsefor仅当您用尽了可迭代对象时才会执行on a loop，因此当您没有提前退出循环时。

您的姓氏是该行的第一个值，因此最好测试该行是否以姓氏开头：

if line.startswith(surname + ','):

专业提示：读取 CSV 文件时，请使用csv模块：

import csv

with open('Address book.csv', newline='') as myfile:
    reader = csv.reader(myfile)
    for row in reader:
        if row[0] == surname:
            print(row)
            break
    else:
         print('No contacts found')