通过索引获取 itertools 对象，类似于你在列表中的获取方式

Question

Are there any quick ways that I can easily derive the index from an itertools.izip object , similar to how you derive from a list ?

I am trying to compare 2 values, one from a list, the other from the itertools object. While I can use enumerate on the object to grab the value, it seems that I will need to iterate all the values within the said object before doing so.

# if iterating from a list
list_values = [(1, 'a', 'john'), (2, 'b', 'jack'), (3, 'c', 'jill')]
print list_values[1] # returns me (2, 'b', 'jack')

# if trying to do the same as above but towards an itertools objext
iter_values = itertools.izip([1, 2, 3], ['a', 'b', 'c'], ['john', 'jack', 'jill'])
print iter_values[1] # Errors-out

Answer 1

No you can't index an iterator. That's the trade-off, you don't have to keep the object in memory, but you don't get random access and indexing. You can slice an iterator with itertools.islice() but it's not an indexing operation of course and consumes the iterator.