# Generate ‘n’ unique random numbers within a range

###### Posted By: Anonymous

I know how to generate a random number within a range in Python.

```
random.randint(numLow, numHigh)
```

And I know I can put this in a loop to generate n amount of these numbers

```
for x in range (0, n):
listOfNumbers.append(random.randint(numLow, numHigh))
```

However, I need to make sure each number in that list is unique. Other than a load of conditional statements, is there a straightforward way of generating n number of unique random numbers?

The important thing is that each number in the list is different to the others..

So

[12, 5, 6, 1] = good

But

[12, 5, 5, 1] = bad, because the number 5 occurs twice.

## Solution

If you just need sampling without replacement:

```
>>> import random
>>> random.sample(range(1, 100), 3)
[77, 52, 45]
```

random.sample takes a population and a sample size `k`

and returns `k`

random members of the population.

If you have to control for the case where `k`

is larger than `len(population)`

, you need to be prepared to catch a `ValueError`

:

```
>>> try:
... random.sample(range(1, 2), 3)
... except ValueError:
... print('Sample size exceeded population size.')
...
Sample size exceeded population size
```

###### Answered By: Anonymous

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