Random number between 0 and 1 in python [duplicate]

Answer 1

RTM

From the docs for the Python random module:

Functions for integers:

random.randrange(stop)
random.randrange(start, stop[, step])

    Return a randomly selected element from range(start, stop, step).
    This is equivalent to choice(range(start, stop, step)), but doesn’t
    actually build a range object.

That explains why it only gives you 0, doesn't it. range(0,1) is [0]. It is choosing from a list consisting of only that value.

Also from those docs:

random.random()    
    Return the next random floating point number in the range [0.0, 1.0).

But if your inclusion of the numpy tag is intentional, you can generate many random floats in that range with one call using a np.random function.

Answer 2

I want a random number between 0 and 1, like 0.3452

random.random() is what you are looking for:

From python docs: random.random() Return the next random floating point number in the range [0.0, 1.0).

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And, btw, Why your try didn't work?:

Your try was: random.randrange(0, 1)

From python docs: random.randrange() Return a randomly selected element from range(start, stop, step). This is equivalent to choice(range(start, stop, step)), but doesn’t actually build a range object.

So, what you are doing here, with random.randrange(a,b) is choosing a random element from range(a,b); in your case, from range(0,1), but, guess what!: the only element in range(0,1), is 0, so, the only element you can choose from range(0,1), is 0; that's why you were always getting 0 back.

Answer 3

random.randrange(0,2) this works!

Answer 4

You can use random.uniform

import random
random.uniform(0, 1)

Answer 5

My variation that I find to be more flexible.

str_Key           = ""
str_FullKey       = "" 
str_CharacterPool = "01234ABCDEFfghij~-)"
for int_I in range(64): 
    str_Key = random.choice(str_CharacterPool) 
    str_FullKey = str_FullKey + str_Key 

Answer 6

random.random() does exactly that

>>> import random
>>> for i in range(10):
...     print(random.random())
... 
0.908047338626
0.0199900075962
0.904058545833
0.321508119045
0.657086320195
0.714084413092
0.315924955063
0.696965958019
0.93824013683
0.484207425759

If you want really random numbers, and to cover the range [0, 1]:

>>> import os
>>> int.from_bytes(os.urandom(8), byteorder="big") / ((1 << 64) - 1)
0.7409674234050893