Let's assume that I wanna collect n lists as an input. What I used to do was:
l=[]
for i in range(n):
row=map(int,raw_input().split())
l.append(row)
And then I used to access those list by l[0],l[1],...,l[n].
Is there any more elegant way to do this? I mean like creating variables dynamically within the for loop with names like: row1,row2,...,rown ?
Anytime you ask yourself how you could create dynamic variables, the answer is "use a dictionary".
l=dict()
for i in range(n):
k='row%d'%(i,)
l[k] = map(int, raw_input().split())
l=dict( ('row%d'%(i,), map(int, raw_input().split())) for i in range(n) or something even more elegant.It might seem like a good idea at first, but once you've tried it you'll probably realise that polluting your namespace is inelegant
The usual way to create the list is this nested list comprehension
rows = [[int(j) for j in i] for i in raw_input().split()]
You can throw map in there if it's clearer to you
rows = [map(int, i) for i in raw_input().split()]
Then you have rows[0], rows[1]... etc which is not all that different to row0 row1... and is far more acceptable namespace wise
In my opinion, this is definitely the best way of storing an arbitrary number of integers. You really don't want to create variables on the fly, mainly because of how you use them later. For example, if you want to use number 23, you can easily do l[22] to get your number, and to take care of cases where <23 numbers were input:
try:
print l[22]
except IndexError:
print "No element 22!"
It would be much harder just using a different variable name to call a possibly undeclared variable.
Additionally, this way you can use len(l) to find out how many numbers you have, whereas with variables, you'd have to do something messy with locals() and it's not a great idea.
las a variable name, as PEP8 warns, it looks too much like1in some fonts