I have the following code, and the idea is to be able to iterate over root for each string in some_list[j]. The goal is to stay away from nested for loops and learn a more pythonic way of doing this. I would like to return each value for the first item in some_list then repeat for the next item in some_list.
for i, value in enumerate(root.iter('{0}'.format(some_list[j])))
return value
Any ideas?
EDIT: root is
tree = ElementTree.parse(self._file)
root = tree.getroot()
I think what you're trying to do is this:
values = ('{0}'.format(root.iter(item)) for item in some_list)
for i, value in enumerate(values):
# ...
But really, '{0}'.format(foo) is silly; it's just going to do the same thing as str(foo) but more slowly and harder to understand. Most likely you already have strings, so all you really need is:
values = (root.iter(item) for item in some_list)
for i, value in enumerate(values):
# ...
You could merge those into a single line, or replace the genexpr with map(root.iter, some_list), etc., but that's the basic idea.
At any rate, there are no nested loops here. There are two loops, but they're just interleaving—you're still only running the inner code once for each item in some_list.
So, given List A, which contains multiple lists, you want to return the first element of each list? I may not be understanding you correctly, but if so you can use a list comprehension...very "Pythonic" ;)
In [1]: some_list = [[1,2,3],[4,5,6],[7,8,9]]
In [2]: new = [x[0] for x in some_list]
In [3]: new
Out[3]: [1, 4, 7]
You could try using chain()
from the itertools module. It would look something like
from itertools import chain
all_items = chain(*[root.iter('{0}'.format(x) for x in some_list)])
for i, value in enumerate(all_items):
return value # or yield i, value, or whatever you need to do with value
returnstatement does first. What do you want to do with these values?yield? I would like to push them to another function for further processing.