CODEWITHSUNDEEP
pythonlistrandom
Jesse
Jesse

Reputation: 25

Trying to get my program to not duplicate random numbers

I am asking the program to print out the numbers 1 through 9 in a random order, in a grid. The problem is that when it prints out, it will have the same numbers twice. Here is the code that I have so far:`import random rows = 3 cols = 3

values = [[0,0,0]]

for r in range(rows):
    for c in range(cols):
        values [r][c] = random.randint(1, 9)
        print(values)

`

and an example output: [[6, 0, 0]] [[6, 4, 0]] [[6, 4, 2]]

also, those double brackets are annoying. any way to fix that?

Upvotes: 0

Views: 106

Answers (2)

Alex Martelli
Alex Martelli

Reputation: 882781

Use random.shuffle to randomize the order of the numbers you want:

import random

numbers = list(range(1, rows * cols + 1))  # good for Py 2 *and* 3
random.shuffle(numbers)
values = [[0] * cols for r in rows]

(the latter to avoid duplicates in values and make it the right size -- I don't see how your original code could fail to raise exceptions!).

then:

for r in range(rows):
    for c in range(cols):
        values[r][c] = numbers(r + rows * c)
    print(values[r])

which also removes the double brackets (assuming you want single ones) and only prints each row once (your original indentation would print the whole matrix many, many times:-).

Upvotes: 2

dslack
dslack

Reputation: 845

If you don't mind using numpy, try numpy.random.shuffle().

Example:

import numpy
xx = numpy.arange(10)
numpy.random.shuffle(xx)
print xx

Upvotes: 0

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