Python总是打印其他的政治家

Question

我有这样的代码：

from tabulate import tabulate

def search_movie_title():
    movies = open('movies.txt','r').readlines()
    title = input("Input movie title: ").lower()
    for i in movies:
        movie = i.strip("\n").split("|")
        if title == movie[0].lower():
            table = [['Name:',movie[0]],['Genre:',movie[1]],['Running:',movie[2]],['Director:',movie[3]],['Starring:', movie[4]],['Country:', movie[5]], ['Realised:', movie[6]]]
            print (tabulate(table))
        else:
            print("Nothing found! Try again.")
            search_movie_title()

文本文件如下：

A fistful of Dolars|Western|100|Sergio Leone|Clint Eastwood|Italia|1964
For a few dolars more|Western|130|Sergio Leone|Clint Eastwood|Italia|1965
The Good, the Bad and the Ugly|Western|179|Sergio Leone|Clint Eastwood|Italia|1966
March on the Drina|War movie|107|Zika Mitrovic|LJuba Tadic|Serbia|1964

如果我只使用if语句，它工作得“很好”，但如果我输入了不存在的电影，那么程序就会停止运行，很明显。你知道吗

如果我使用if和else，它将始终打印else语句（文本文件中的第一行除外）

问题是：如何只打印找到的电影和电影，如果找不到电影，如何打印消息？你知道吗

Answer 1

使用^{}：

movie = next((movie for movie in movies
              if movie.split('|')[0] == title),
             None)

if movie:
    movie = movie.strip().split('|')
    fields = ['Name:', 'Genre:', 'Running:', 'Director:', 'Starring:', 'Country:', 'Realised:']
    table = list(zip(fields, movie))
    print (tabulate(table))
else:
    print("Nothing found! Try again.")

Answer 2

您可以使用python for-else：

from tabulate import tabulate

def search_movie_title():
    movies = open('movies.txt','r').readlines()
    title = input("Input movie title: ").lower()
    for i in movies:
        movie = i.strip("\n").split("|")
        if title == movie[0].lower():
            table = [['Name:',movie[0]],['Genre:',movie[1]],['Running:',movie[2]],['Director:',movie[3]],['Starring:', movie[4]],['Country:', movie[5]], ['Realised:', movie[6]]]
            print (tabulate(table))
            break
    else:
        print("Nothing found! Try again.")

    # optionally add code here to be run regardless

只有在for循环没有中断的情况下，else才会执行。通过这种方式，您可以添加以后运行的代码，无论是否找到电影（而不是立即返回）

Answer 3

必须确保迭代所有电影（for i in movies），直到可以确定是否找到了电影。所以：遍历所有电影，打印电影，如果找到它，就从函数返回。如果你在遍历了所有的电影之后还没有找到电影，那么请用户再试一次。你知道吗

from tabulate import tabulate

def search_movie_title():
    movies = open('movies.txt','r').readlines()
    title = input("Input movie title: ").lower()
    for i in movies:
        movie = i.strip("\n").split("|")
        if title == movie[0].lower():
            table = [['Name:',movie[0]],['Genre:',movie[1]],['Running:',movie[2]],['Director:',movie[3]],['Starring:', movie[4]],['Country:', movie[5]], ['Realised:', movie[6]]]
            print (tabulate(table))
            return

    print("Nothing found! Try again.")
    search_movie_title()

我建议只打印“NothingFound”，然后返回，而不是递归调用函数。你知道吗