CODEWITHSUNDEEP
pythonlist
Gabriel_W
Gabriel_W

Reputation: 1865

Python - Create a List Starting at a Given Value and End at Given Length

How can I create a list that will have a starting value and length of the list. For example, if I wanted to make a list starting at 17 that was of length 5:

num_list = [17, 18, 19, 20, 21]

I have tried the following however it is not producing the correct results

def answer(start, length):
id_arr = list(range(start, length))
print(id_arr)

answer(17, 10)

Output: []

And I understand the reason for this because, the starting value, in this case, is 17, however, it is trying to end at value 10 thus creating an empty list so how can I make the value of length be the size of the list and not the ending value of the list?

Upvotes: 6

Views: 38361

Answers (6)

VarunT
VarunT

Reputation: 31

in your def

id_arr = list(range(start, start+length))

should give you the desired result

Upvotes: 3

Ashish
Ashish

Reputation: 4330

The built-in range function in Python is very useful to generate sequences of numbers in the form of a list. If we provide two parameters in range The first one is starting point, and second one is end point. The given end point is never part of the generated list. So we can use this method:

def answer(start, length):
    id_arr = [list_items for list_items in range(start, start + length)]
    print id_arr


answer (17, 5)
>> [17, 18, 19, 20, 21]

Upvotes: 1

Shivkumar kondi
Shivkumar kondi

Reputation: 6762

range function itself does all that for you.

range(starting value, endvalue+1, step)

so you can go for range(17,22)

If you writing custom function then go for:

def answer(start, length):
    id_arr = list(range(start, start+length))
    print(id_arr)

answer(17, 5)

output :
[17, 18, 19, 20, 21]

Upvotes: 11

Akshay Apte
Akshay Apte

Reputation: 1653

just append to list till range.

def answer(start,length):
    anslist=[start]
    for ans in range(length):
        anslist.append(start+ans)
    print anslist

Upvotes: 1

Manpreet Ahluwalia
Manpreet Ahluwalia

Reputation: 331

def answer(start, length):
    id_arr = list(range(start, start+length))
    print(id_arr)

answer(17, 5)

Upvotes: 1

kzawisto
kzawisto

Reputation: 76

Not really, first argument is lower bound and the second is upper bound in terms of half open interval.

list(range(10,20))

[10, 11, 12, 13, 14, 15, 16, 17, 18, 19]

Upvotes: 1

Related Questions