Meaning of list[-1] in Python - Stack Overflow
I have a piece of code here that is supposed to return the least common element in a list of elements, ordered by commonality: def getSingle(arr): from collections import Counter c = …
What is the difference between list[1] and list[1:] in Python?
Oct 5, 2012 · By using a : colon in the list index, you are asking for a slice, which is always another list. In Python you can assign values to both an individual item in a list, and to a slice …
Python: list of lists - Stack Overflow
The first, [:], is creating a slice (normally often used for getting just part of a list), which happens to contain the entire list, and thus is effectively a copy of the list. The second, list(), is using the …
How do I make a flat list out of a list of lists? - Stack Overflow
If your list of lists comes from a nested list comprehension, the problem can be solved more simply/directly by fixing the comprehension; please see How can I get a flat result from a list …
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 …
How can I pass a list as a command-line argument with argparse?
Don't use quotes on the command line 1 Don't use type=list, as it will return a list of lists This happens because under the hood argparse uses the value of type to coerce each individual …
How to group dataframe rows into list in pandas groupby
Given a dataframe, I want to groupby the first column and get second column as lists in rows, so that a dataframe like: a b A 1 A 2 B 5 B 5 B 4 C 6 becomes A [1,2] B [5,5,4] C [6] How do I do …
Most efficient way to find if a value exists within a C# List
Apr 17, 2013 · In C# if I have a List of type bool. What is the fastest way to determine if the list contains a true value? I don’t need to know how many or where the true value is. I just need to …
Get unique values from a list in python - Stack Overflow
Oct 15, 2012 · 1537 First declare your list properly, separated by commas. You can get the unique values by converting the list to a set.
Get a list from Pandas DataFrame column headers - Stack Overflow
I want to get a list of the column headers from a Pandas DataFrame. The DataFrame will come from user input, so I won't know how many columns there will be or what they will be called. …