L
lokeshkoppaka
i need to write a code which can sort the list in order of 'n' without use builtin functions
can anyone help me how to do?
can anyone help me how to do?
help how to sort a list in order of 'n' in python without usinginbuilt functions??
C
Chris Angelico
D
Dave Angel
You could sort, but you couldn't print out the results, so what's the
point? In Python 3.3 at least, print() is a built-in function.
Is the homework assignment more clearly worded than your summary? And
if so, how far have you gotten on it?
C
Carlos Nepomuceno
lol wtf?
If 'n' is the quantity of elements to be sorted there's
no way you can write an algorithm with complexity O(n) for the worst
case not knowing something special about the data.
For example, Quicksort will give you O(n*(log(n)) on average case (O(n^2)in the worst case).
You gotta be much more specific than that if you really need an O(n) code.
There's probably assumptions you didn't mention about the data if O(n) it'sreally what you're looking for.
PS: Looks like a joke as stated..
----------------------------------------
If 'n' is the quantity of elements to be sorted there's
no way you can write an algorithm with complexity O(n) for the worst
case not knowing something special about the data.
For example, Quicksort will give you O(n*(log(n)) on average case (O(n^2)in the worst case).
You gotta be much more specific than that if you really need an O(n) code.
There's probably assumptions you didn't mention about the data if O(n) it'sreally what you're looking for.
PS: Looks like a joke as stated..
----------------------------------------
L
lokeshkoppaka
Note:
the list only contains 0's,1's,2's
need to sort them in order of 'n'
C
Chris Angelico
In that case, you're not really ordering them, you're counting them.
Look at the collections module; you can very easily figure out how
many of each there are, and then reconstruct the list afterward.
ChrisA
L
lokeshkoppaka
but i need to do it with out using builtin functions
R
rusi
C
Chris Angelico
Depending on your definitions, that's either trivially easy (the
'collections' module is not builtin functions) or completely
impossible. Have fun.
ChrisA
S
Steven D'Aprano
How would you, an intelligent human being count them?
Describe how you would count them in English, or whatever your native
language is.
"First I would start a tally for the number of zeroes, tally = 0. Then I
look at each item in turn, and if it is 0, I add one to the tally. When I
get to the end, I the number of zeroes is equal to the tally.
Then I do the same for the number of ones, and the number of twos."
Now turn that into Python code.
tally = 0
for item in list_of_items:
if item == 0:
tally = tally + 1
print "The number of zeroes equals", tally
L
lokeshkoppaka
ya steven i had done the similar logic but thats not satisfying my professor
he had given the following constrains
1. No in-built functions should be used
2. we are expecting a O(n) solution
3. Don't use count method
C
Chris Angelico
And now you finally admit that it's homework.
Solve it yourself, or go to your prof and say that you need help.
ChrisA
C
Carlos Nepomuceno
----------------------------------------
That's trivial!
# l is a list of numbers: 0,1,2
def order_n(l):
r = []
count = [0]*3
count[2] = len(l)
for i in range(len(l)):
count[1] += abs((l>0)-1)
r.insert(count[l], l)
return r
'count' is a list I've defined to count the quantity of the elements in theargument, not the method.
I don't think it needs any explanations, but if you have any doubts just ask.
Good luck!
That's trivial!
# l is a list of numbers: 0,1,2
def order_n(l):
r = []
count = [0]*3
count[2] = len(l)
for i in range(len(l)):
count[1] += abs((l>0)-1)
r.insert(count[l], l)
return r
'count' is a list I've defined to count the quantity of the elements in theargument, not the method.
I don't think it needs any explanations, but if you have any doubts just ask.
Good luck!
C
Chris Angelico
Fail!
ChrisA
C
Carlos Nepomuceno
----------------------------------------
lol I forgot to include this monkey patch!
def length(l):
x=0
y=l[:]
while y:
x+=1
y.pop()
return x
Date: Sat, 25 May 2013 18:28:32 +1000
Subject: Re: help how to sort a list in order of 'n' in python without using inbuilt functions??
From: (e-mail address removed)
To: (e-mail address removed)
Fail!
ChrisA
lol I forgot to include this monkey patch!
def length(l):
x=0
y=l[:]
while y:
x+=1
y.pop()
return x
C
Chris Angelico
----------------------------------------
lol I forgot to include this monkey patch!
def length(l):
x=0
y=l[:]
while y:
x+=1
y.pop()
return x
Nice. Now eliminate abs (easy) and range.
ChrisA
C
Carlos Nepomuceno
lol
def absolute(x):
return x if x>0 else -x
def reach(x):
y=[]
z=0
while z<x:
y.append(z)
z+=1
return y
----------------------------------------
def absolute(x):
return x if x>0 else -x
def reach(x):
y=[]
z=0
while z<x:
y.append(z)
z+=1
return y
----------------------------------------
Date: Sat, 25 May 2013 18:47:24 +1000
Subject: Re: help how to sort a list in order of 'n' in python without using inbuilt functions??
From: (e-mail address removed)
To: (e-mail address removed)
----------------------------------------
lol I forgot to include this monkey patch!
def length(l):
x=0
y=l[:]
while y:
x+=1
y.pop()
return x
Nice. Now eliminate abs (easy) and range.
ChrisA
C
Chris Angelico
Very good. You are now in a position to get past the limitations of a
restricted-environment eval/exec. Avoiding builtins is actually a fun
skill to hone.
ChrisA
C
Carlos Nepomuceno
----------------------------------------
I'm glad he didn't ask for a Pseudo-RNG without built-ins!
I'm glad he didn't ask for a Pseudo-RNG without built-ins!
C
Chris Angelico
----------------------------------------
I'm glad he didn't ask for a Pseudo-RNG without built-ins!
def random_number():
return 7
ChrisA