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- Meaning of list[-1] in Python - Stack Overflow
All your return c most_common()[-1] statement does is call c most_common and return the last value in the resulting list, which would give you the least common item in that list Essentially, this line is equivalent to:
- What is the difference between list[1] and list[1:] in Python?
slicing is used to extract a sublist of a list where as indexing is used to retrive a specific element of list slicedList = aList[beginIndex:endIndex] d[1:] refers to slicing the list d - refer to this - This is slicing c[1] is an element of the list c - this is indexing
- What is the difference between list and list [:] in python?
When reading, list is a reference to the original list, and list[:] shallow-copies the list When assigning, list (re)binds the name and list[:] slice-assigns, replacing what was previously in the list Also, don't use list as a name since it shadows the built-in
- 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
- 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
- What is the difference between Pythons list methods append and extend . . .
my_list + another_list creates a third list in memory, so you can return the result of it, but it requires that the second iterable be a list my_list += another_list modifies the list in-place (it is the in-place operator, and lists are mutable objects, as we've seen) so it does not create a new list It also works like extend, in that the
- python - if else in a list comprehension - Stack Overflow
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 range(5)] for example
- How to list all installed packages and their versions in Python?
For Windows 10, I think this is what you are looking for a list of available installed Pythons This is different from a list of packages as you can see below Also, on Ubuntu 20 04, I think the command is Python3 -0 list Yes, this works similar to node version manager c:\Users\user\AppData\Local\Programs\Python>py -0 list Python 0 not found!
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