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I'd like to know what happens when I pass the result of a generator function to python's enumerate(). Example:
def veryBigHello(): i = 0 while i < 10000000: i += 1 yield "hello" numbered = enumerate(veryBigHello()) for i, word in numbered: print i, word Is the enumeration iterated lazily, or does it slurp everything into the <enumerate object> first? I'm 99.999% sure it's lazy, so can I treat it exactly the same as the generator function, or do I need to watch out for anything?
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What does enumerate do in Python? The enumerate function in Python converts a data collection object into an enumerate object. Enumerate returns an object that contains a counter as a key for each value within an object, making items within the collection easier to access.
In this example, you assign the return value of enumerate() to enum . enumerate() is an iterator, so attempting to access its values by index raises a TypeError . Fortunately, Python's enumerate() lets you avoid all these problems.
Enumerate() in PythonEnumerate() method adds a counter to an iterable and returns it in a form of enumerating object. This enumerated object can then be used directly for loops or converted into a list of tuples using the list() method.
enumerate() allows us to iterate through a sequence but it keeps track of both the index and the element. The enumerate() function takes in an iterable as an argument, such as a list, string, tuple, or dictionary.
It's lazy. It's fairly easy to prove that's the case:
>>> def abc(): ... letters = ['a','b','c'] ... for letter in letters: ... print letter ... yield letter ... >>> numbered = enumerate(abc()) >>> for i, word in numbered: ... print i, word ... a 0 a b 1 b c 2 c If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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