How to iterate through dict in random order in Pyt

问题:

How can I iterate through all items of a dictionary in a random order? I mean something random.shuffle, but for a dictionary.

回答1:

A dict is an unordered set of key-value pairs. When you iterate a dict, it is effectively random. But to explicitly randomize the sequence of key-value pairs, you need to work with a different object that is ordered, like a list. dict.items(), dict.keys(), and dict.values() each return lists, which can be shuffled.

items=d.items() # List of tuples
random.shuffle(items)
for key, value in items:
    print key, value

keys=d.keys() # List of keys
random.shuffle(keys)
for key in keys:
    print key, d[key]

Or, if you don't care about the keys:

values=d.values() # List of values
random.shuffle(values) # Shuffles in-place
for value in values:
    print value

You can also "sort by random":

for key, value in sorted(d.items(), key=lambda x: random.random()):
    print key, value

回答2:

You can't. Get the list of keys with .keys(), shuffle them, then iterate through the list while indexing the original dict.

Or use .items(), and shuffle and iterate that.

回答3:

As Charles Brunet have already said that the dictionary is random arrangement of key value pairs. But to make it really random you will be using random module. I have written a function which will shuffle all the keys and so while you are iterating through it you will be iterating randomly. You can understand more clearly by seeing the code:

def shuffle(q):
    """
    This function is for shuffling 
    the dictionary elements.
    """
    selected_keys = []
    i = 0
    while i < len(q):
        current_selection = random.choice(q.keys())
        if current_selection not in selected_keys:
            selected_keys.append(current_selection)
            i = i+1
    return selected_keys

Now when you call the function just pass the parameter(the name of the dictionary you want to shuffle) and you will get a list of keys which are shuffled. Finally you can create a loop for the length of the list and use name_of_dictionary[key] to get the value. Hope this will add a value to this stack :)

Source: Radius Of Circle