I wanted to generate 1 or -1 in `Python` as a step to randomizing between non-negative and non-positive numbers or to randomly changing sign of an already existing integer. What would be the best way to generate 1 or -1 in `Python`? Assuming even distribution I know I could use:

```
import random

#method1
my_number = random.choice((-1, 1))

#method2
my_number = (-1)**random.randrange(2)

#method3
# if I understand correctly random.random() should never return exactly 1
# so I use "<", not "<="
if random.random() < 0.5:
    my_number = 1
else:
    my_number = -1

#method4
my_number = random.randint(0,1)*2-1

```

Using `timeit` module I got the following results:

```
#method1
s = "my_number = random.choice((-1, 1))"
timeit.timeit(stmt = s, setup = "import random")
>2.814896769857569
#method2
s = "my_number = (-1)**random.randrange(2)"
timeit.timeit(stmt = s, setup = "import random")
>3.521280517518562
#method3
s = """
if random.random() < 0.5: my_number = 1
else: my_number = -1"""
timeit.timeit(stmt = s, setup = "import random")
>0.25321546903273884
#method4
s = "random.randint(0,1)*2-1"
timeit.timeit(stmt = s, setup = "import random")
>4.526625442240402

```

So unexpectedly method 3 is the fastest. My bet was on method 1 to be the fastest as it is also shortest. Also both method 1 (since `Python 3.6` I think?) and 3 give the possibility to introduce uneven distributions. Although method 1 is shortest (main advantege) for now I would choose method 3:

```
def positive_or_negative():
    if random.random() < 0.5:
        return 1
    else:
        return -1

```

Testing:

```
s = """
import random
def positive_or_negative():
    if random.random() < 0.5:
        return 1
    else:
        return -1
        """
timeit.timeit(stmt = "my_number = positive_or_negative()", setup = s)
>0.3916183138621818

```

Any better (faster or shorter) method to randomly generate -1 or 1 in `Python`? Any reason why would you choose method 1 over method 3 or vice versa?