Need help with coding a function in Python
Larry Hudson
orgnut at yahoo.com
Mon Oct 31 22:26:03 EDT 2016
On 10/31/2016 03:09 PM, devers.meetthebadger.jason at gmail.com wrote:
> http://imgur.com/a/rfGhK#iVLQKSW
>
> How do I code a function that returns a list of the first n elements of the sequence defined in the link? I have no idea!!!!!
>
> So far this is my best shot at it (the problem with it is that the n that i'm subtracting or adding in the if/else part does not represent the element's position, but just the n that I am plugging into the function):
>
> def reca(n):
> rlist=[0]
> while len(rlist) < n:
> if (rlist[-1]-n) > 0 and (rlist[-1]-n) not in rlist:
> rlist.append(rlist[-1]-n)
>
> else:
> rlist.append(rlist[-1]+n)
>
> return(rlist)
>
I'm not looking at your link or your code, just your description of the problem.
Paraphrased: "A list of the first n elements of a sequence"
No function necessary, just use slicing...
newlist = oldlist[:n]
list: [1,2,3,4,5,6,7,8,9,10][:5] gives [1,2,3,4,5]
tuple: (1,2,3,4,5,6,7,8,9,10)[:5] gives (1,2,3,4,5)
string: "Hello there"[:5] gives "Hello"
Works for sequences shorter than n as well, which gives the full (short) sequence.
list: [1,2,3][:5] gives [1,2,3]
etc...
--
-=- Larry -=-
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