Strange behavior when passing a function as second parameter of the `setdefault` dictionary method Question: I don’t understand the behavior of setdefault in this scenario: def f(x): return x+1 dct = {5: 15} print(dct.setdefault(5, f(5))) The key 5 is in the dictionary, but instead of returning the value 15 immediately, it wastes time computing the …
python dict: get vs setdefault Question: The following two expressions seem equivalent to me. Which one is preferable? data = [(‘a’, 1), (‘b’, 1), (‘b’, 2)] d1 = {} d2 = {} for key, val in data: # variant 1) d1[key] = d1.get(key, []) + [val] # variant 2) d2.setdefault(key, []).append(val) The results are the …
Use cases for the 'setdefault' dict method Question: The addition of collections.defaultdict in Python 2.5 greatly reduced the need for dict‘s setdefault method. This question is for our collective education: What is setdefault still useful for, today in Python 2.6/2.7? What popular use cases of setdefault were superseded with collections.defaultdict? Asked By: Eli Bendersky || …
