list.count() is a O(N) job (all elements in the list are compared to count) and you are doing this in a loop over N elements, giving you quadratic performance, O(N^2). So for a 10-element list 100 …

To select rows not in list_of_values, negate isin()/in: df[~df['A'].isin(list_of_values)] df.query("A not in @list_of_values") # df.query("A != @list_of_values") 5. Select rows where multiple columns …

Jun 17, 2009 · List<String> places = Arrays.asList("Buenos Aires", "Córdoba", "La Plata"); Or if you have only one element: List<String> places = Collections.singletonList("Buenos Aires"); …

Sep 14, 2015 · 1. A list is used as if it were a dictionary 1.1. Index a list as if it was a dictionary. This case commonly occurs when a json object is converted into a Python object but there's a …

Oct 15, 2012 · Because it inherits from a list, it basically acts like a list, so you can use functions like index() etc. And because it returns true or false, you can find out if appending succeeded …

Since a list comprehension creates a list, it shouldn't be used if creating a list is not the goal; it shouldn't be used simply to write a one-line for-loop; so refrain from writing [print(x) for x in …

I prefer passing a delimited string which I parse later in the script. The reasons for this are; the list can be of any type int or str, and sometimes using nargs I run into problems if there are …

Dec 22, 2017 · This will create a 2D list of array, where every row is a unique array of values in each column. If you would like a 2D list of lists, you can modify the above to …

Nov 1, 2011 · def make_unique(original_list): unique_list = [] [unique_list.append(obj) for obj in original_list if obj not in unique_list] return unique_list Some may consider list comprehension …

Jul 26, 2010 · This command will give you a list of all top-level objects inside an AWS S3 bucket: aws s3 ls bucket-name. This command will give you a list of ALL objects inside an AWS S3 …