Looping between different lists in python

Question

I'm trying to pull different data sets from SQL into python using different lists. For example I have the following data:

years = [2006, 2007, 2008]
2006 = [A, B, C, D, E]
2007 = [D, E, F, G, H, I, J, K]
2008 = [E, F, G]

Then to pull the data in, I'm using the following formulas:

df = pd.read_sql('SELECT %s from Table' % (str(x)), con=conn)

I'd like the string, str(x), to loop through each year first, then use the list for the corresponding year.

So, first it should do 2006 and loop through the 2006 list (A, B, C, D, E), run the rest of the program, then move on to 2007 and 2008.

I've used loops before but not sure how to loop between different lists.

cr3 · Accepted Answer · 2016-01-06 02:56:34Z

3

If I understand correctly, you might want to express your data hierarchically:

years = {
    2006: ['A', 'B', 'C', 'D', 'E'],
    2007: ['D', 'E', 'F', 'G', 'H', 'I', 'J', 'K'],
    2008: ['E', 'F', 'G'],
}

You could then loop over the years and then over the letters for each year like this:

for year, letters in years.items():
    # do something per year
    for letter in letters:
        # do something per letter for the year

Does this answer your question?

answered Jan 6, 2016 at 2:56

cr3

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Comments

Thomas · Accepted Answer · 2016-01-06 03:12:31Z

1

Another advantage of cr3 solution is, you can address the items of each year easily, like:

print years[2006]

for y in years[2006]:
    print y

answered Jan 6, 2016 at 3:12

Thomas

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