[thatOnekid]

Hey all, was playing with Python and came across some problems. I wanted to prompt the user for the minimum array size, size of array increment, and number of test arrays. The arrays will be used to generate sort time data for arrays of different sizes. Then use a random number generator to create an array of the desired size etc. and then sort the array using
the desired algorithm and time the sort. But the problem was how do I create multiple lists in one go? I wrote up some code that creates a random list based on some user info given.

def whichFunction():
    loop = 1
    choice = 0
    while loop == 1:
        print "Welcome to the cool sorting function!"
        user_choice = input("Which sorting function would you like to use? Type 1-3.\n 
1. BubbleSort\n 2. QuickSort\n 3. Isort\n ")

        sortingType = input("Which type of data pattern would you like? Type 1-3\n 
1.Random\n 2.sorted\n 3.reverse sorted\n")
 
       n = input("What is the minimum array size?")
       x = input("what is the size of array increments?")
       y = input("What is the number of test arrays?")

       # a = [[] for i in range(y)]                                             

        a = [random.randint(0,x) for r in xrange(n)]
        print a

and received

[1, 0, 2, 0, 2, 2, 2, 2, 2, 1]

for n = 10, x=2, y=2

Now the MAIN question is, how do i create "y" number of lists that can be implemented into my while loop, that will be sorted into my bubble sort, quick sort, or insertion sort based on my user preference. Thanks, I can post my sorting functions if needed, though they are pretty standard.

[atraub]

You basically already had it:

import random
def whichFunction():
    choice = 0
    while True:
        print "Welcome to the cool sorting function!"
        user_choice = input("Which sorting function would you like to use? Type 1-3.\n 1. BubbleSort\n 2. QuickSort\n 3. Isort\n ")

        sortingType = input("Which type of data pattern would you like? Type 1-3\n 1.Random\n 2.sorted\n 3.reverse sorted\n")
 
        n = input("What is the minimum array size?")
        x = input("what is the size of array increments?")
        y = input("What is the number of test arrays?")

        a= []                                             
        for i in range(y):
            a.append([random.randint(0,x) for r in xrange(n)])
        print a

EDIT:
if you REALLY want to do a 1 liner, you could use

import random
def whichFunction():
    choice = 0
    while True:
        print "Welcome to the cool sorting function!"
        user_choice = input("Which sorting function would you like to use? Type 1-3.\n 1. BubbleSort\n 2. QuickSort\n 3. Isort\n ")

        sortingType = input("Which type of data pattern would you like? Type 1-3\n 1.Random\n 2.sorted\n 3.reverse sorted\n")
 
        n = input("What is the minimum array size?")
        x = input("what is the size of array increments?")
        y = input("What is the number of test arrays?")

        a = [([random.randint(0,x) for r in xrange(n)]) for i in range(y)]
        print a

but that looks ugly and is hard to read, which is exactly what you don't want to do in python

Edit 2:
Also, might I suggest better variable names? n, x, y, a are not very descriptive.

This post has been edited by atraub: 28 April 2012 - 07:29 PM
Reason for edit:: for completeness

[thatOnekid]

...Wow, thank you so much! Not sure why I couldn't think of it. Mind helping me with sorting functions...getting some errors when i try to run them. And any idea whats a good way to run the timing function? Below is my entire python program.

import numpy
import random
import sys
from time import clock

def whichFunction():
    loop = 1
    choice = 0
    while loop == 1:
        print "Welcome to the cool sorting function!"
        user_choice = input("Which sorting function would you like to use? Type 1-3.\n 1. BubbleSort\n 2. QuickSort\n 3. Isort\n ")

        sortingType = input("Which type of data pattern would you like? Type 1-3\n 1.Random\n 2.sorted\n 3.reverse sorted\n")
        n = input("What is the minimum array size?")
        x = input("what is the size of array increments?")
        y = input("What is the number of test arrays?")

        a= []
        for i in range(y):
            a.append([random.randint(0,x) for r in xrange(n)])
        print a
        if user_choice == 1:
            """ bubble sort """

         #takes in a,n                                                                                                                                                                                                                     
            for m in reversed(xrange(0,n+1)):
                for i in xrange(0,m-1):
                    if a[i] > a[i+1]:
                        t = a[i]# inlineswap                                                                                                                                                                                       
                        a[i] = a[i+1]
                        a[i+1] = t

            if sortingType == 1:
                a = random.shuffle(t)
                print a
                return a
            if sortingType == 2:
                print sorted(a)
                return a
            if sortingType == 3:
                a = sorted(a, cmp=reverse_numeric)
                print a
                return a
       if user_choice == 2:
            """ quick sort """
            if a == []:
                return []
            else:
                pivot = a[0]
                lesser = qsort1([x for x in a[1:] if x < pivot])
                greater = qsort1([x for x in a[1:] if x >= pivot])
                a = lesser + [pivot] + greater
                if sortingType == 1:
                    print random.shuffle(a)
                    return a
		if sortingType == 2:
                    print sorted(a)
                    return a
                if sortingType == 3:
                    a = sorted(a, cmp=reverse_numeric)
                    print a
                    return a
        if user_choice == 3:
            """ Isort """
          # takes a and n                                                                                                                                                                                                                  
            for i in xrange(1,n):
                j = 1
                while j>0 and a[j-1]>a[j]:
                    a[j-1],a[j] =a[j],a[j-1]
                    j -=1
            if sortingType == 1:
                print random.shuffle(a)
                return a
            if sortingType == 2:
                print sorted(a)
                return a
            if sortingType == 3:
                a = sorted(a, cmp=reverse_numeric)
                print a
                return a


def reverse_numeric(x, y):
        return y - x

[atraub]

Getting times is easy in python

import time

startTime = time.time()

#do your sorting here

elapsedTime = time.time() - startTime

As for your errors, could you be more specific? If you don't mind, copy and paste the exact error message, in code tags preferably.

Also, welcome to Dream In Code! The best way to thank someone here is to click on the + sign at the bottom of their post

[thatOnekid]

Yeah, I chose variables to go smoothly into sorting functions, though I guess I could leave some doc strings.

I tried running my program, and it went something like this.

Which sorting function would you like to use? Type 1-3.
 1. BubbleSort
 2. QuickSort
 3. Isort
 1
Which type of data pattern would you like? Type 1-3
 1.Random
 2.sorted
 3.reverse sorted
1
What is the minimum array size?10
what is the size of array increments?10
What is the number of test arrays?2
[[0, 0, 3, 7, 8, 1, 5, 10, 9, 0], [7, 3, 8, 10, 7, 2, 7, 7, 3, 9]]
Traceback (most recent call last):
  File "main.py", line 96, in <module>
    main()    
  File "main.py", line 95, in main
    whichFunction()
  File "main.py", line 31, in whichFunction
    if a[i] > a[i+1]:
IndexError: list index out of range
>>> 

This post has been edited by atraub: 28 April 2012 - 08:17 PM
Reason for edit:: no need to quote the entire post

[atraub]

here's your first problem, you're putting a into the bubble sort, but a holds 2 lists. you want to use the lists inside of a.

Also, let's break those sorting algorithms into functions. Here's an example for bubbleSort:

def bubbleSort(numberList):
    for m in reversed(xrange(0,len(numberList)+1)):
        for i in xrange(0,m-1):
            if numberList[i] > numberList[i+1]:
                t = numberList[i]# inlineswap
                numberList[i] = numberList[i+1]
                numberList[i+1] = t

here's a more pythonic version of bubble sort

def bubbleSort(numberList):
    for m in reversed(xrange(0,len(numberList)+1)):
        for i in xrange(0,m-1):
            if numberList[i] > numberList[i+1]:
                numberList[i],numberList[i+1]=numberList[i+1],numberList[i]

Here's an example using the interpreter:

>>> a = [[1,8,3,7,2],[2,6,3,8,9]]
>>> for eachList in a:
	bubbleSort(eachList)

	
>>> a
[[1, 2, 3, 7, 8], [2, 3, 6, 8, 9]]
>>> 

EDIT:
Oh, for fun, let's not forget timing

>>> a = [[1,8,3,7,2],[2,6,3,8,9]]
>>> times = []
>>> for eachList in a:
	startTime = time.time()
	bubbleSort(eachList)
	times.append(time.time() - startTime)

	
>>> a
[[1, 2, 3, 7, 8], [2, 3, 6, 8, 9]]
>>> times
[0.0, 0.0]
>>> 

What happened? The code executed so fast that the time measurement didn't pick anything up, for a much bigger set, that would't happen

Edit 2 - better example:

>>> a = []
>>> for i in range(4):
	a.append([random.randint(1,1000) for i in range(1500)])

	
>>> times = []
>>> for eachList in a:
	start = time.time()
	bubbleSort(eachList)
	times.append(time.time() - start)

	
>>> times
[0.31100010871887207, 0.31599998474121094, 0.31299996376037598, 0.3059999942779541]

This post has been edited by atraub: 28 April 2012 - 08:06 PM

[thatOnekid]

Genius! slowly trying to fix my code, and fix minor bugs but your help is invaluable! thanks so much. Duly noted on the +1 on comments.

This post has been edited by atraub: 28 April 2012 - 08:14 PM
Reason for edit:: no need to quote me

[atraub]

Glad it helped boss! Feel free to post again if you hit anymore snags.

[thatOnekid]

Dang, I almost got my program done, just got stuck on quicksort.

What is the minimum array size?10
what is the size of array increments?100
What is the number of test arrays?2
a: [[65, 83, 25, 51, 78, 10, 81, 99, 72, 67], [1, 43, 71, 2, 34, 95, 95, 48, 70, 43]]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "main2.py", line 60, in main
    QuickSort(eachList)
  File "main2.py", line 90, in QuickSort
    sortedList = quickSort(low)
NameError: global name 'quickSort' is not defined

Am i supposed to import something into my file?? Code looks like:

def QuickSort(numberList):
    a = numberList
    if len(a) <= 1:
	return a
    end = len(a) -1
    pivot = a[end]
    low = []
    high = []
    for num in a[:end:]:
	if num <= pivot:
            low.append(num)
	else:
            high.append(num)

    sortedList = quickSort(low)
    sortedList.appned(pivot)
    sortedList.extend(quickSort(high))
    return sortedList

[Simown]

The error:

NameError: global name 'quickSort' is not defined

Your function is called "QuickSort" and then your recursive call calls "quickSort" (lower case q) on line 17.

Change one of them so they match and you should be set

[thatOnekid]

Worked Great, Thanks for the help all! Program done and now the fun part!! (taking various test cases and timing my functions!!)

[atraub]

Incidentally, there's a little error in your quicksort code, but that could just be from copying and pasting it into DIC. The code under your first condition isn't indented.

[thatOnekid]

Yeah, just copied it badly. Though I had some problems trying to write the results to a file. I am trying to write it where every time I run the main(), I ask user if they want to save. I gotten that part down, but when I run the code a second time, it removes what ever was saved in the file. Trying to keep all results in the file so i could import it to excel and graph each sorting function result.

  alogrithm = user_choice
        print "Alogrithm:%s" %(alogrithm)
        print "Input Data:%s"%(inputData)
        print "  n      time (secs)"
        print "_"*50
        print n,sum(times),
        info = n,sum(times)
        saveit = raw_input("Would you like to save it to a file? (y/n)")
        if saveit == 'y':
            whichFile = raw_input("Which file would you like to save it to?")
            fo = open(whichFile,"w")
            fo.write("n  time \n")
            fo.write("_"*50)
            fo.write(str(info))
            fo.close()
        if saveit == 'n':
            print " Ok, wont save"
        quit = raw_input("Would you like to quit or repeat? (q / r)")
        if quit == 'q':
            exit()
        else:
            pass

When I run the program, this is what i get.

Which sorting function would you like to use? Type 1-3.
 1. BubbleSort
 2. Insertion Sort
 3. QuickSort
 3
Which type of data pattern would you like? Type 1-3
 1.Random
 2.sorted
 3.reverse sorted
2
What is the minimum array size?20
what is the size of array increments?20
What is the number of test arrays?2
a: [[19, 18, 5, 7, 6, 11, 7, 11, 2, 10, 18, 3, 0, 3, 0, 14, 7, 16, 4, 11], [12, 18, 12, 14, 15, 14, 14, 16, 5, 4, 0, 12, 0, 11, 18, 10, 2, 18, 15, 5]]
Alogrithm:3
Input Data:Sorted
  n      time
__________________________________________________
20 0.000219106674194 secs
Would you like to save it to a file? (y/n)y
Which file would you like to save it to?test2.csv
Would you like to quit or repeat? (q / r)q

[atraub]

fo = open(whichFile,"w") should be fo = open(whichFile,"a") . Write mode overwrites, you want append mode.

EDIT:
Also, you may want to make writing to your file a function:

alogrithm = user_choice
      print "Alogrithm:%s" %(alogrithm)
      print "Input Data:%s"%(inputData)
      print "  n      time (secs)"
      print "_"*50
      print n,sum(times),
      info = n,sum(times)
      saveit = raw_input("Would you like to save it to a file? (y/n)")
      if saveit == 'y':
          saveFile()
      if saveit == 'n':
          print " Ok, wont save"
      quit = raw_input("Would you like to quit or repeat? (q / r)")
      if quit == 'q':
          exit()
      else:
          pass



def saveFile(info, whichFile = false): #this allows you to optionally provide a filename
    if not whichFile:
        whichFile = raw_input("Which file would you like to save it to?")
    fo = open(whichFile,"a")
    fo.write("n  time \n" + ("_"*50) + str(info))
    fo.close()

This post has been edited by atraub: 29 April 2012 - 11:51 AM

[thatOnekid]

Never mind, figured it out!! I had to append the wanted information.

whichFile = raw_input("Which file would you like to save it to?")
            with open(whichFile, "a") as fo:
		fo.write("n  time(secs) \n")
                fo.write(str(info))
            fo.close()

Well that's all folks! Thanks again for the BIG help.