I have been banging my head against this for two days now. I am new to python and programming so the other examples of this type of error have not helped me to much. I am reading through the documentation for lists and tuples, but haven’t found anything that helps. Any pointer would be much appreciated.…
Tag: list
Assign a value to a list of variables using a loop
I can do this in C, but I haven’t come across it in Python. Say I have a few variables: and I have list of values [1, 2, 3, 4] how can I assign the values to the variables with a single loop so I get the following result: Answer While you technically can modify local variables, doing so is
Explanation of how nested list comprehension works?
I have no problem understanding this: I thought that was all, but then I found this snippet: Which makes b = [1,2,3,4,5,6]. The problem is I’m having trouble understanding the syntax in [x for xs in a for x in xs], Could anyone explain how it works? Answer Ah, the incomprehensible “nested” c…
How does the max() function work on list of strings in python?
I have a list: It gives: Please also explain how it perform comparison on list of strings and list of numbers. Answer This is actually a good question and the answer varies depending on whether you’re on python2.x or python3.x … And which python implementation you’re using1. See here for a d…
Index all *except* one item in python
Is there a simple way to index all elements of a list (or array, or whatever) except for a particular index? E.g., mylist[3] will return the item in position 3 milist[~3] will return the whole list except for 3 Answer For a list, you could use a list comp. For example, to make b a copy of a without the
Find matching values in a list of lists
I’m trying to iterate over a list of lists in python 2.7.5 and return those where the first value is found in a second list, something like this: So I would want list3 to contain [[‘aa’,1,3,7],[‘bc’, 3, 4, 4]] but instead I just get the whole of list2. Answer Try a more simple ap…
Access multiple elements of list knowing their index [duplicate]
This question already has answers here: Explicitly select items from a list or tuple (9 answers) Closed 7 months ago. I need to choose some elements from the given list, knowing their index. Let say I would like to create a new list, which contains element with index 1, 2, 5, from given list [-2, 1, 5, 3, 8, …
How can I use list comprehensions to process a nested list?
I have this nested list: I want to convert each element in l to float. I have this code: How can I solve the problem with a nested list comprehension instead? See also: How can I get a flat result from a list comprehension instead of a nested list? Answer Here is how you would do this with a nested
cross product in python of arbitrarily many lists
I know you can take the pairwise cross product of lists in the ways posted here: Pairwise crossproduct in Python but I want to take a list L and a positive integer n and return the cross-product of L with itself n times. Is there a built in way to do this or will I just have to iterate the
Convert range(r) to list of strings of length 2 in python
I just want to change a list (that I make using range(r)) to a list of strings, but if the length of the string is 1, tack a 0 on the front. I know how to turn the list into strings using but I want to be able to also change the length of those strings. Input: Output: And if