Difference between Python dictionary comprehension and loop -

i using python 3.4, , testing out dictionary comprehension.

let's have following code:

listofdict = [{"id":1, "title": "asc", "section": "123"},{"id":2, "title": "ewr", "section": "456"}] titles1 = [] titles2 = [] titles1.append({r["section"]: r["title"] r in listofdict}) print("titles1 = " + str(titles1))  r in listofdict:   section = r["section"]   title = r["title"]   titles2.append({section: title})  print("titles2 = " + str(titles2)) 

i thought both methods should give me same result, following instead:

titles1 = [{'456': 'ewr', '123': 'asc'}] titles2 = [{'123': 'asc'}, {'456': 'ewr'}] 

titles2 want, want use dictionary comprehension it.

what right way write dictionary comprehension?

you cannot use dict comprehension that, because dict comprehension produces one dictionary keys , values taken loop(s).

you'd use list comprehension instead:

[{r["section"]: r["title"]} r in listofdict] 

this produces 1 dictionary each iteration, producing new list:

>>> listofdict = [{"id":1, "title": "asc", "section": "123"},{"id":2, "title": "ewr", "section": "456"}] >>> [{r["section"]: r["title"]} r in listofdict] [{'123': 'asc'}, {'456': 'ewr'}]