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- List of zeros in python - Stack Overflow
See why [] is faster than list() There is a gotcha though, both itertools repeat and [0] * n will create lists whose elements refer to same id This is not a problem with immutable objects like integers or strings but if you try to create list of mutable objects like a list of lists ([[]] * n) then all the elements will refer to the same object
- Identify duplicate values in a list in Python - Stack Overflow
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 steps are executed, for a 1000 element list 1 million, etc –
- Use a list of values to select rows from a Pandas dataframe
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 are in list_of_values If you want to filter using both (or multiple) columns, there's any() and all() to reduce columns (axis=1) depending on the
- Sorting a list with stream. sorted() in Java - Stack Overflow
Java 8 provides different utility api methods to help us sort the streams better If your list is a list of Integers(or Double, Long, String etc ,) then you can simply sort the list with default comparators provided by java
- TypeError: list indices must be integers or slices, not str
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 dictionary nested inside a list It is especially annoying (and easy to overlook) if the list has a single dictionary inside it
- What is the difference between an Array, ArrayList and a List?
Also, System Array supports multiple dimensions (i e it has a Rank property) while List and ArrayList do not (although you can create a List of Lists or an ArrayList of ArrayLists, if you want to) An ArrayList is a flexible array which contains a list of objects You can add and remove items from it and it automatically deals with allocating
- slice - How slicing in Python works - Stack Overflow
The first way works for a list or a string; the second way only works for a list, because slice assignment isn't allowed for strings Other than that I think the only difference is speed: it looks like it's a little faster the first way Try it yourself with timeit timeit() or preferably timeit repeat()
- c# - define a List like List lt;int,string gt;? - Stack Overflow
List<(int,string)> mylist= new List<(int,string)>(); Which creates a list of ValueTuple type If you're targeting NET Framework 4 7+ or NET NET Core, it's native, otherwise you have to get the ValueTuple package from nuget It's a struct opposing to Tuple, which is a class
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