Python random and int to string question

Question

Hi,

I am using this line of code to generate a random list of integers:

random.sample(range(2000), 100)

With this code i know i wont have double value's with my result. Is their maybe a faster way to achieve the same results?

Now i actually have to convert these int to string. Whats the fastest way to do this?

Thanks

Answer 1

random.sample chooses integers from the list without replacement. If you are trying to avoid duplicates then what you are doing is the right method. Could your numbers get much larger? You need to use Python 3, or xrange in Python 2 to avoid generating the entire list of integers in the range.

(Thanks to J.F. Sebastian for pointing out that random.sample does NOT have to generate all integers if you use xrange.)

If you want to allow duplicates you can use randrange instead:

randomInts = [random.randrange(2000) for _ in range(100)]

To convert to strings:

randomStrings = [str(x) for x in randomInts]

Answer 2

import random
r = random.sample(range(2000), 100)
# One way to convert them to strings:
s = [str(x) for x in r]

Answer 3

If you'll be generating lots and lots of lists of random numbers, you can pre-generate the strings to accelerate the lookup, something like this.

stringcache = dict((val, str(val)) for val in range(2000))

while some_condition: 
    r_strings = map(stringcache.get, random.sample(range(2000), 100))

Answer 4

Use xrange instead of range:

lst = random.sample(xrange(10**9), 100)

To convert to a list of strings:

strings = map(str, lst)

As one string:

s = ''.join(strings)