Question

Let’s say I have a list:

a = ['apple', 'carrot']

and a dictionary:

d ={'apple': [2,4], 'carrot': [44,33], 'orange': [345,667]}

How can I use the list a as a key to lookup in the dictionary d? I want the result to be written to a comma-separated textfile like this

apple,    carrot
2,        44
4,        33

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Corrected the a-list from a = [‘apple’, ‘orange’] to a = [‘apple’, ‘carrot’]

Answer 1

I know other people have been faster and their solutions are similar, but here’s my take (take it or leave it):

a = ['apple', 'orange']

d ={'apple': [2,4], 'carrot': [44,33], 'orange': [345,667]}

fo = open('test.csv','w')
fo.write(',\t'.join(a)+'\n')
for y in xrange(len(d[a[0]])):
    fo.write(',\t'.join([str(d[i][y]) for i in a])+'\n')

fo.close()

which generates the file test.csv:

apple,  orange
2,      345
4,      667