Nested List comprehension

Question

I have 2 lists, A and B.

A is list of dictionaries which contain list of values.
B is a simple list.

Requirement is to add the elements of list B into dictionary values of A.

Below is the code,

a = [{'a':[1,5]}, {'b' : [6,10]}, {'c' : [11,15]}]
b = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]

for i in a:
  for k,j in i.items():
      for m,n in enumerate(b):
          if j[0]<= n<=j[1]:
              j.append(n)

print(a)

[{'a':[1,5,1,2,3,4,5]}, {'b' : [6,10,6,7,8,9,10]}, {'c' : 
[11,15,11,12,13,14,15]}]

# tried list comprehension
a= [{k:n} for i in a for k,j in i.items() for m,n in enumerate(b)
if j[0]<= n<=j[1]]

print(a)

[{'a': 1}, {'a': 2}, {'a': 3}, {'a': 4}, {'a': 5}, {'b': 6}, {'b': 7}, 
{'b': 8}, {'b': 9}, {'b': 10}, {'c': 11}, {'c': 12}, {'c': 13}, {'c': 
14}, {'c': 15}]

Question is whether this can be done using list comprehension? I have tried but unable to generate the required output.

Błotosmętek · Accepted Answer · 2017-07-08 08:00:49Z

3

a = [{k: [ x for x in b if v[0] <= x <= v[1] ]} for d in a for k,v in d.items()]

answered Jul 8, 2017 at 8:00

Błotosmętek

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Comments

Wasi Ahmad · Accepted Answer · 2017-07-08 08:31:40Z

2

Just a small modification of the @Błotosmętek answer to get exactly what you need as output.

a = [{'a': [1, 5]}, {'b': [6, 10]}, {'c': [11, 15]}]
b = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

a = [{k: v+[x for x in b if v[0]<=x<=v[1]]} for d in a for k, v in d.items()]
print(a)

Output

[{'a': [1, 5, 1, 2, 3, 4, 5]}, {'b': [6, 10, 6, 7, 8, 9, 10]}, {'c': [11, 15, 11, 12, 13, 14, 15]}]

edited Jul 8, 2017 at 8:31

answered Jul 8, 2017 at 8:11

Wasi Ahmad

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2 Comments

Ganesh Over a year ago

Thanks for the modified solution

Błotosmętek Over a year ago

Wasn't obvious from the description, but if we take OP's solution as reference then yes, your modification is necessary.

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