3rd argument of python range [duplicate] - python

This question already has answers here:
Python's `range` function with 3 parameters
(3 answers)
Closed 5 years ago.
I am trying to create a list of lists using a list comprehension method. I found this solution online:
output = [1,2,3,4,5,6]
[output[i:i+2] for i in range(0, len(output), 2)]
This is the first time I have come across a 3rd argument in range, What does the 3rd argument of range do?

The 3rd argument of range is the stepping, meaning how much to increment the last value for:
>>> for i in range (0,10,2):
... print i
0
2
4
6
8

Related

Creating a list or range with all numbers up to a certain variable [duplicate]

This question already has answers here:
How do I create a list with numbers between two values?
(12 answers)
Closed 17 days ago.
So I am defining a function that takes in one variable R. Then I need to create a list of all integers from 0 to R (in the context of the problem R will always be positive).
EX) When I do
R=5
print(list(0,R))
I just get a list with 2 elements: 0 and 5, but I want 0,1,2,3,4,5
The range() function returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and stops before a specified number.
range(6) would return [0,1,2,3,4,5]

How to find position of big value in python list array [duplicate]

This question already has answers here:
Pythonic way to find maximum value and its index in a list?
(11 answers)
Getting the index of the returned max or min item using max()/min() on a list
(23 answers)
Closed 1 year ago.
list = [3,5,1,8,9]
I want to find positions of the maximum value in the list
This is pretty simple, but it will give you the index of the first occurrence:
>>> l = [3,5,1,8,9]
>>> l.index(max(l))
4
I strongly suggest you not use the name of built-in functions as list for variables.

Iterate over even indices in a list [duplicate]

This question already has answers here:
split list into 2 lists corresponding to every other element [duplicate]
(3 answers)
Closed 4 years ago.
Say i have this list:
CP = [1,0,1,0]
How can i print only 0's in the list via indices i.e CP[i].
Required output:
0
0
Any help would be highly appreciated!
This feels like a homework problem, and I assume you actually want odd indices instead of even indices.
Here's a possible solution:
# get a range of all odd numbers between 1 and length of list
# with a step size of 2
for i in range(1, len(CP), 2):
print(CP[i])
The one liner --
print ('\n'.join([str(CP[i]) for i in range(1, len(CP), 2)]))

Python min function tuples with arbitrary tuples [duplicate]

This question already has answers here:
How does tuple comparison work in Python?
(4 answers)
Closed 5 years ago.
What is this python code doing?
min((2,3),(6,'f',1))
Output: (2, 3)
I am not able to follow the documentation.
Can someone explain why the output in (2,3) and not an error?
Because (2,3) < (6,'f',1)
Meaning tuples are compared itemwise, therefore 2 < 6 yields that the first tuple is less than the second one
While this code works on Python 2 and Python 3, it should fail on Python 3 if both items in 1st place were the same. Because it would compare 3 to the string 'f' and such comparison is now invalid.
The min function will call the comparator methods of the objects you pass. In this case, all tuples. It is returning the minimum tuple with respect to lexicographic order.

how to define a list with predefined length in Python [duplicate]

This question already has answers here:
Create a list with initial capacity in Python
(11 answers)
Closed 9 years ago.
I want to do the following :
l = list()
l[2] = 'two'
As expected, that does not work. It returns an out of range exception.
Is there any way to, let say, define a list with a length ?
Try this one
values = [None]*1000
In place of 1000 use your desired number.

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