Python 如何从字典中打印特定的键值？

How to print Specific key value from a dictionary?

提问by Irakli

fruit = {
    "banana": 1.00,
    "apple": 1.53,
    "kiwi": 2.00,
    "avocado": 3.23,
    "mango": 2.33,
    "pineapple": 1.44,
    "strawberries": 1.95,
    "melon": 2.34,
    "grapes": 0.98
}

for key,value in fruit.items():
     print(value)

I want to print the kiwi key, how?

我想打印奇异果钥匙，怎么办？

print(value[2]) 

This is not working.

这是行不通的。

回答by Joe Iddon

Python's dictionaries have no order, so indexing like you are suggesting (fruits[2]) makes no sense as you can't retrieve the second element of something that has no order. They are merely sets of key:valuepairs.

Python 的字典没有 order，因此像您建议的 ( fruits[2])索引没有任何意义，因为您无法检索没有顺序的内容的第二个元素。它们只是key:value成对的集合。

To retrieve the value at key: 'kiwi', simply do: fruit['kiwi']. This is the most fundamental way to access the value of a certain key. See the documentationfor further clarification.

要检索的值key：'kiwi'，简单地做：fruit['kiwi']。这是访问某个键值的最基本方式。请参阅文档以获取进一步说明。

And passing that into a print()call would actually give you an output:

并将其传递给print()调用实际上会给你一个输出：

print(fruit['kiwi'])
#2.0

---

---

Note how the 2.00is reduced to 2.0, this is because superfluous zeroes are removed.

注意 是如何2.00减少到 的2.0，这是因为多余的零被删除了。

---

---

Finally, if you want to use a for-loop(don't know why you would, they are significantly more inefficient in this case (O(n)vs O(1)for straight lookup)) then you can do the following:

最后，如果您想使用 a for-loop（不知道为什么会这样，在这种情况下它们的效率要低得多（O(n)与O(1)直接查找相比）），那么您可以执行以下操作：

for k, v in fruit.items():
    if k == 'kiwi':
        print(v)
#2.0

回答by arundeepak

fruit = {
    "banana": 1.00,
    "apple": 1.53,
    "kiwi": 2.00,
    "avocado": 3.23,
    "mango": 2.33,
    "pineapple": 1.44,
    "strawberries": 1.95,
    "melon": 2.34,
    "grapes": 0.98
}

for key,value in fruit.items():
    if value == 2.00:
         print(key)

I think you are looking for something like this.

我想你正在寻找这样的东西。

回答by Alan Hoover

You can access the value of key 'kiwi' with

您可以访问密钥 'kiwi' 的值

print(fruit['kiwi'])

回答by MOHANPAL SINGH

You can simply print by using below command

您可以使用以下命令简单地打印

print(fruit['kiwi'])

If you want to check whether a key has been successfully added or not, use below command:

如果要检查密钥是否已成功添加，请使用以下命令：

print('key' in dictionary)

for eg: print('New york' in USA)

例如： print('New york' in USA)

回答by Abhisek Roy

Is this what you are looking for?

这是你想要的？

fruit = {
    "banana": 1.00,
    "apple": 1.53,
    "kiwi": 2.00,
    "avocado": 3.23,
    "mango": 2.33,
    "pineapple": 1.44,
    "strawberries": 1.95,
    "melon": 2.34,
    "grapes": 0.98
}

for key in fruit:
     print(fruit[key],"=",key)

回答by Abhisek Roy

If you only want to display the Kiwi field.

如果您只想显示 Kiwi 字段。

fruit = {
    "banana": 1.00,
    "apple": 1.53,
    "kiwi": 2.00,
    "avocado": 3.23,
    "mango": 2.33,
    "pineapple": 1.44,
    "strawberries": 1.95,
    "melon": 2.34,
    "grapes": 0.98
}

print(fruit["kiwi"],"=kiwi")

回答by ColonelFazackerley

def reverse_dict(dictionary, lookup_val):
    for key,value in fruit.items():
        if abs(lookup_val-value) < 0.01:
            return key

fruit = {
    "banana": 1.00,
    "apple": 1.53,
    "kiwi": 2.00,
    "avocado": 3.23,
    "mango": 2.33,
    "pineapple": 1.44,
    "strawberries": 1.95,
    "melon": 2.34,
    "grapes": 0.98
}

for key,value in fruit.items():
    print("{}:{}".format(key, value))

print(fruit['kiwi'])
print(reverse_dict(fruit, 2.00))

Many reasons for caution

谨慎的原因很多

1. This will get slow with a large dict
2. only first match will be returned
3. your value is a float, so a tolerance is needed: I picked 0.01

1. 这会因大字典而变慢
2. 只会返回第一场比赛
3. 你的值是一个浮点数，所以需要一个公差：我选择了 0.01