修改字典的所有键 [英] Altering all keys of a dictionary

问题描述

是否可以重命名/更改字典的所有键?作为示例，让我们看一下以下字典:

  a_dict = {'a_var1':0.05，'a_var2':4.0，'a_var3':100.0，'a_var4':0.3} 

我想删除键中的所有 a _ ，所以我最终得到了

  a_dict = {'var1':0.05，'var2':4.0，'var3':100.0，'var4':0.3} 

解决方案

如果您想更改现有的字典，而不是创建一个新的字典，可以循环键， pop 旧的，然后插入具有旧值的新的，经过修改的密钥.

 >>>对于列表中的k(a_dict):... a_dict [k [2:]] = a_dict.pop(k)...>>>a_dict{'var2':4.0，'var1':0.05，'var3':100.0，'var4':0.3} 

(对 list(a_dict)进行迭代将防止由于并发修改而导致的错误.)

严格来说，这也不会更改现有密钥，而是插入新密钥，因为它必须根据其新的哈希码重新插入它们.但这确实改变了整个字典.

---

如注释中所述，实际上，循环更新字典中的键可能比对字典的理解要慢.如果存在问题，您还可以使用dict理解来创建新的dict，然后清除现有的dict并 update 使用新值.

 >>>b_dict = {k [2:]:a_dict中的k用a_dict [k]}>>>a_dict.clear()>>>a_dict.update(b_dict) 

Is it possible to rename/alter all the keys of a dict? As an example, let's look at the following dictionary:

a_dict = {'a_var1': 0.05,
          'a_var2': 4.0,
          'a_var3': 100.0,  
          'a_var4': 0.3}

I want to remove all the a_ in the keys, so I end up with

a_dict = {'var1': 0.05,
          'var2': 4.0,
          'var3': 100.0,  
          'var4': 0.3}

解决方案

If you want to alter the existing dict, instead of creating a new one, you can loop the keys, pop the old one, and insert the new, modified key with the old value.

>>> for k in list(a_dict):
...     a_dict[k[2:]] = a_dict.pop(k)     
...
>>> a_dict
{'var2': 4.0, 'var1': 0.05, 'var3': 100.0, 'var4': 0.3}

(Iterating a list(a_dict) will prevent errors due to concurrent modification.)

Strictly speaking, this, too, does not alter the existing keys, but inserts new keys, as it has to re-insert them according to their new hash codes. But it does alter the dictionary as a whole.

---

As noted in comments, updating the keys in the dict in a loop can in fact be slower than a dict comprehension. If this is a problem, you could also create a new dict using a dict comprehension, and then clear the existing dict and update it with the new values.

>>> b_dict = {k[2:]: a_dict[k] for k in a_dict}
>>> a_dict.clear()
>>> a_dict.update(b_dict)

这篇关于修改字典的所有键的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！