I’m trying to find a way to use one list to filter out elements of another. Kinda like the intersect syntax but the exact opposite expected outcome Answer Simple way: or
Tag: list
Calculating arithmetic mean (one type of average) in Python [duplicate]
This question already has answers here: Finding the average of a list (25 answers) Closed 12 months ago. Is there a built-in or standard library method in Python to calculate the arithmetic mean (one type of average) of a list of numbers? Answer I am not aware of anything in the standard library. However, you…
Fastest way to check if a value exists in a list
What is the fastest way to check if a value exists in a very large list? Answer Clearest and fastest way to do it. You can also consider using a set, but constructing that set from your list may take more time than faster membership testing will save. The only way to be certain is to benchmark well. (this als…
Print a list in reverse order with range()?
How can you produce the following list with range() in Python? Answer use reversed() function: It’s much more meaningful. Update: If you want it to be a list (as btk pointed out): Update: If you want to use only range to achieve the same result, you can use all its parameters. range(start, stop, step) F…
How to Query model where name contains any word in python list?
Aim to Achieve: I want all objects where name attribute contains any word from the list. I have: For example: if name=”this is word2″: Then object with such a name should be returned since word2 is in the list. Please help! Answer You could use Q objects to constuct a query like this: Edit: is a f…
Dictionary keys match on list; get key/value pair
In python… I have a list of elements ‘my_list’, and a dictionary ‘my_dict’ where some keys match in ‘my_list’. I would like to search the dictionary and retrieve key/value pairs for the keys matching the ‘my_list’ elements. I tried this… But it doesn…
Joining pairs of elements of a list [duplicate]
This question already has answers here: How to iterate over a list in chunks (39 answers) Closed 8 months ago. I know that a list can be joined to make one long string as in: Obviously this would output: However, what I am trying to do is simply join the first and second strings in the list, then join the
[] and {} vs list() and dict(), which is better? [closed]
Closed. This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 6 months ago. The community reviewed whether to reopen this question 6 months ago and left it closed: Or…
List sorting/modify problem
Initially, I wasn’t sure whether this was the appropriate place for this question, but after reading through the FAQ I feel fairly confident the topic is acceptable…. Furthermore I wasn’t sure if this would be classified as a particular type of problem (eg. a knapsack problem), thus, the tit…
Fast way to remove a few items from a list/queue
This is a follow up to a similar question which asked the best way to write and it seems the consensus was on something like However, I think if you are only removing a few items, most of the items are being copied into the same object, and perhaps that is slow. In an answer to another related question, someo…