The value of the Python iteration Dict

The value of the iteration Dict

1:values ()

2:itervalues ()

3:forkey inDi:

    print (Di[key])

We have learned that the Dict object itself is an iterative object , iterating the dict directly with a for loop, and can get a key for dict each time.

What should we do if we want to iterate over the value of the Dict object?

The Dict object has a values () method , which converts the dict into a list that contains all value, so that we iterate over each value of Dict:

D = {' Adam ':}print, ' Lisa ': $, ' Bart ': D.values () # [59], 59]for V in D.values ():    print v# 85# 95#

If you read the Python document carefully, you can also see that dict, in addition to the values () method, has a itervalues ( ) method that replaces The Itervalues () method with the The values () method, the iteration effect is exactly the same:

D = {' Adam ': +, ' Lisa ': $, ' Bart ':}print d.itervalues () # <dictionary-valueiterator object at 0x106adbb50>for V in D.itervalues ():    print v# 85# 95# 59

What is the difference between the two methods?

1. The values () method actually converts a dict to a list containing value.

2. However, the itervalues () method does not convert, and it takes value from dict in sequence during the iteration, so the Itervalues () method saves the memory needed to generate the list, compared to the values () method.

3. Print itervalues () find it returns a <dictionary-valueiterator> object, which shows that in Python, thefor loop can be used to iterate beyond list,tuple,str. Unicode,dict, and so on , any iterator object can be used for a for loop, and the inner iteration of how we usually don't care.

If an object says that it can iterate, then we iterate it directly with a for loop, which is an abstract data operation that does not require any data inside the iteration object.

The value of the Python iteration Dict