安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
|
- 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 syntax to insert one list into another list in python?
List slicing is quite flexible as it allows to replace a range of entries in a list with a range of
- How can I find the index for a given item in a list?
@stefanct this likely does double the complexity, I believe the in operator on a list has linear runtime @ApproachingDarknessFish stated it would iterate twice which answers your question, and is right in saying that doubling the linear complexity is not a hu
- 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
- 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
- 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()
- 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
- How to concatenate (join) items in a list to a single string
@Wouter, it will not On the one hand, only lists of strings can be joined; so list join would be inappropriate for an arbitrary list On the other, the argument of str join can be any "iterable" sequence of strings, not just a list
|
|
|