CODEWITHSUNDEEP
pythonlistrange
Lumos
Lumos

Reputation: 1383

create a python list with fixed steps but no fixed limits

I have a question about list. My list needs to be around a midpoint with minimum of 1, and it needs 6 integer steps (+/-) evenly around the midpoint, with step of 1. There will be 7 digits (midpoint + 6 steps) in the list.

e.g.,if mid = 10, then the list = [7,8,9,**10**,11,12,13]. 3 steps above 10 and 3 steps below 10. But if mid = 3, the digits then can't distribute evenly with 3 steps above and under the midpoint, because the minimum is 1. To ensure 7 items in the list, 4 steps above 3 and 2 steps under 3. Thus, [1,2,**3**,4,5,6,7]. If the mid=2, 5 steps above 2 and 1 step under 2. The list is still [1,**2**,3,4,5,6,7].
Here is my code:

def gain_range(mid):

    gainLower_list = list(range(1, mid)) #items under the midpoint
    gainUpper_list = list(range(mid, n)) #items above the midpoint, hence I can combine the two lists later
    if mid >= 4:
       n = mid + 3
    elif mid >= 3:
       n = mid + 4
    elif mid >= 2:
       n = mid + 5
    elif mid >= 1:
       n = mid + 6        

gain_range(3)

but this codes gives an error:

UnboundLocalError: local variable 'n' referenced before assignment

How should I fix this? And is there more elegant way to create this list with fixed steps, rather than fixed limits?

Upvotes: 0

Views: 208

Answers (2)

Verbal_Kint
Verbal_Kint

Reputation: 1416

Just addressing the error here: you use the variable n in your code before you have declared it.

def gain_range(mid):

    gainLower_list = list(range(1, mid))
    gainUpper_list = list(range(mid, n))  # use n here but is hasnt been declared and assigned a value
    if mid >= 4:
       n = mid + 3
    elif mid >= 3:
       n = mid + 4
    elif mid >= 2:
       n = mid + 5
    elif mid >= 1:
       n = mid + 6

You need to assign a value to n before then...

However, if you just want 6 evenly distributed, consecutive digits surrounding mid with a minimum of 1 then the answer above mine (Steven Rausch) should do the trick

Upvotes: 0

Stephen Rauch
Stephen Rauch

Reputation: 49774

The only decision needed is for the starting value which must be >= 1, so calculate that first, then just return a list from range:

Code:

def gain_range(mid):
    start = max(1, mid - 3)
    return list(range(start, start+7))

Test Code:

print(gain_range(3))
print(gain_range(4))
print(gain_range(5))

Results:

[1, 2, 3, 4, 5, 6, 7]
[1, 2, 3, 4, 5, 6, 7]
[2, 3, 4, 5, 6, 7, 8]

Upvotes: 1

Related Questions