Python - Count elements in list [duplicate]

This question already has answers here: How do I get the number of elements in a list (length of a list) in Python? (11 answers) Closed 6 years ago.

I am trying to find a simple way of getting a count of the number of elements in a list:

MyList = ["a", "b", "c"]

I want to know there ar开发者_StackOverflow中文版e 3 elements in this list.

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len()

>>> someList=[]
>>> print len(someList)
0

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just do len(MyList)

This also works for strings, tuples, dict objects.

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len(myList) should do it.

len works with all the collections, and strings too.

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len() 

it will count the element in the list, tuple and string and dictionary, eg.

>>> mylist = [1,2,3] #list
>>> len(mylist)
3
>>> word = 'hello' # string 
>>> len(word)
5
>>> vals = {'a':1,'b':2} #dictionary
>>> len(vals)
2
>>> tup = (4,5,6) # tuple 
>>> len(tup)
3

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To find count of unique elements of list use the combination of len() and set().

>>> ls = [1, 2, 3, 4, 1, 1, 2]
>>> len(ls)
7
>>> len(set(ls))
4

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You can get element count of list by following two ways:

>>> l = ['a','b','c']
>>> len(l)
3

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>>> l.__len__() 
3

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Len won't yield the total number of objects in a nested list (including multidimensional lists). If you have numpy, use size(). Otherwise use list comprehensions within recursion.