Question: I want to generate a random number, and that random number should be unique, meaning it should not be repeated or generated again. I have tried making a list where I append in every iteration and check if it is already present in the list or not. If it is present in the list, the number is not appended. But I don't think it is an effective method. So, please help me with it.

```
    import random
    #an empty list to append randomly generated numbers
    empty = []
    while True:
        #checking from range 500 to 510
        number = random.randrange(500, 510)
        if number not in empty:
            empty.append(number)
        else:
            pass
        #breaking the loop if the length of the numbers is 9
        if len(empty) == 9:
            break

    print("Final list --> " + str(empty))

```

Answer: 
You can get such a list of a given number of non-repeating elements taken from a given pool via [**`random.sample`**](https://docs.python.org/3/library/random.html#random.sample):

```
>>> random.sample(range(500, 510), 9)
[500, 501, 503, 502, 505, 507, 508, 506, 504]

```
```
import random
low=int(input("ENTER LOWER RANGE:"))
upper=int(input("ENTER UPPER RANGE:"))
l=[low]
count=1
l=[low]
count=1
if (upper-low)>=c or c==upper:
    while count!=c:
        x=random.randint(low,upper)
        if x not in l:
        l.append(x)
        count+=1

for i in range(len(l)):
    print(l[i])

```