如何搜索字典? [英] How to search through dictionaries?

问题描述

我是Python字典的新手.我正在制作一个简单的程序，它的字典包含四个名称作为键，相应的年龄作为值.我要尝试做的是，如果用户输入一个名称，程序将检查它是否在字典中，如果存在，它应该显示有关该名称的信息.

I'm new to Python dictionaries. I'm making a simple program that has a dictionary that includes four names as keys and the respective ages as values. What I'm trying to do is that if the user enters the a name, the program checks if it's in the dictionary and if it is, it should show the information about that name.

这是我到目前为止所拥有的:

This is what I have so far:

def main():
    people = {
        "Austin" : 25,
        "Martin" : 30,
        "Fred" : 21,
        "Saul" : 50,
    }

    entry = input("Write the name of the person whose age you'd like to know, or write 'ALL' to see all names and ages: ")
    if entry == "ALL":
        for key, value in people.items():
            print ("Name: " + key)
            print ("Age: " + str(value) + "\n")
    elif people.insert(entry) == True:
                print ("It works")

main()

我尝试使用 .index()搜索字典，因为我知道它已在列表中使用，但没有用.我还尝试检查这篇文章，但我没有发现它有用

I tried searching through the dictionary using .index() as I know it's used in lists but it didn't work. I also tried checking this post but I didn't find it useful.

我需要知道是否有任何功能可以做到这一点.

I need to know if there is any function that can do this.

推荐答案

如果您想知道 key 是否是 people 中的键，则可以简单地使用表达式输入人物，例如:

If you want to know if key is a key in people, you can simply use the expression key in people, as in:

if key in people:

并测试它是否不是 people 中的键:

And to test if it is not a key in people:

if key not in people:

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