Python for loop with two related variables

Question

I have a list of names:

names = ['ALICE', 'BOB', 'ME']

Take 'A' as 1, 'B' as 2, 'C' as 3... The sum of 'ALICE' can be calculated with:

sum([ord(i) - ord('A') + 1 for i in 'ALICE'])  // ALICE: 30, BOB: 19, ME: 18

Now, I want to calculate all the sum in names multiplied with index in the names, e.g., 30 * 1 + 19 * 2 + 18 * 3 = 122.

It's easy to do this like:

s = 0
for i in range(len(names)):
    s += sum(([ord(j) - ord('A') + 1) * (i + 1) for j in names[i]])
print s

But I want to learn to do this in list generator style (in one line perhaps). How to do this?

falsetru · Accepted Answer · 2013-10-29 08:31:57Z

3

Using enumerate:

>>> names = ['ALICE', 'BOB', 'ME']
>>> sum(i * sum(ord(ch) - ord('A') + 1 for ch in name) for i, name in enumerate(names, 1))
122

sum accepts any iterable, so you can pass generator expression instead of list comprehension.

>>> enumerate('ALICE')
<enumerate object at 0x7f8f7b8c42d0>
>>> list(enumerate('ALICE'))
[(0, 'A'), (1, 'L'), (2, 'I'), (3, 'C'), (4, 'E')]
>>> list(enumerate('ALICE', 1))
[(1, 'A'), (2, 'L'), (3, 'I'), (4, 'C'), (5, 'E')]

answered Oct 29, 2013 at 8:31

falsetru

371k69 gold badges769 silver badges659 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Python for loop with two related variables

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related