the array.join function takes an optional delimiter parameter which will seperate the elements by the delimiter. A simple example: var showtimes = [“1pm”, “2pm”, “3pm”]; var showtimesAsString = showtimes.join(‘, ‘); // gives “1pm, 2pm, 3pm”
keys, values = zip(*d.items())
all = all[:max(current – 2, 0)] + all[current:] or del all[max(current – 2, 0):current]
Your list of tuples adds an extra layer. You have 3 layers of items: The outer list of length 1 million, so 1 million pointers 1 million 2-slot tuples, so 2 million pointers 2 million references to 1 million integer values while your dict only holds: The dict (including 1 million cached hashes) with 2 … Read more
You can use Select-Object -Last 1 at the end of that pipeline.
You could always just use Data.Sequence. Alternatively, a well-known implementation of a purely functional queue is to use two lists. One for enqueue and another for dequeue. Enqueue would simply cons with the enqueue list. Dequeue takes the head of the dequeue list. When the dequeue list is shorter than the enqueue list, refill it … Read more
If all values are unique then you should reverse the dict first to get an efficient solution: >>> subs = { … “Houston”: “HOU”, … “L.A. Clippers”: “LAC”, … … } >>> rev_subs = { v:k for k,v in subs.iteritems()} >>> [rev_subs.get(item,item) for item in my_lst] [‘L.A. Clippers’, ‘Houston’, ’03/03 06:11 PM’, ‘2.13’, ‘1.80’, ’03/03 … Read more
Python 3 uses iterators for a lot of things where python 2 used lists.The docs give a detailed explanation including the change to range. The advantage is that Python 3 doesn’t need to allocate the memory if you’re using a large range iterator or mapping. For example for i in range(1000000000): print(i) requires a lot … Read more
Add an if into your comprehension like: l = [y for y in (f(x) for x in [1,2,3,4]) if y is not None] By placing a Generator Expression inside the list comprehension you will only need to evaluate the function once. In addition the generator expression is a generator so takes no extra intermediate storage. … Read more
Modern Python 3.x’s can use iterator that has less overhead than constructing a list. first_value = next(iter(my_dict.values())) Note that if the dictionary is empty you will get StopIteration exception and not None. Since Python 3.7+ this is guaranteed to give you the first item.