Переписать числа так что бы в начале были положительные числа, а в конце отрицательные

In [1]: from random import randrange
 
In [2]: a = [randrange(-100_000, 100_000) for _ in range(100_000)]
 
In [3]: %timeit sorted(a, key=lambda x: (x < 0) + (x <= 0))
25.9 ms ± 525 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
 
In [4]: def task(arr):
   ...:     p,pn=[],[]
   ...:     for a in arr:
   ...:         if a>0:
   ...:             p.append(a)
   ...:         else:
   ...:             pn.append(a)
   ...:     p.extend(pn)
   ...:     return p
   ...:
 
In [5]: %timeit task(a)
12.7 ms ± 70.4 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
 
In [6]: %timeit sorted(a, key=lambda x: x < 0)
30.4 ms ± 3.14 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
 
In [7]: %timeit sorted(a, key=lambda x: (abs(x) != x, x==0))
53.7 ms ± 7.01 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

b=list(range(10,-10,-1))

sorted(a, reverse)

from random import randrange
 
a = [randrange(-100_000, 100_000) for _ in range(100_000)]
b = sorted(a, reverse=True)
 
print(a)
print(b)

In [1]: from random import randrange
   ...:
   ...: a = [randrange(-100_000, 100_000) for _ in range(100_000)]
 
In [2]: %timeit sorted(a, reverse=True)
36.2 ms ± 3.47 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
 
In [3]: def task(arr):
   ...:     p,pn=[],[]
   ...:     for a in arr:
   ...:         if a>0:
   ...:             p.append(a)
   ...:         else:
   ...:             pn.append(a)
   ...:     p.extend(pn)
   ...:     return p
   ...:
 
In [4]: %timeit task(a)
12.5 ms ± 180 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

b = sorted(a, reverse=True)

def task(arr):
    p,pn=[],[]
    for a in arr:
        if a>0:
            p.append(a)
        else:
            pn.append(a)
    p.extend(pn)
    return p
    
print(task([1,4,-7,0,12,5,-3]))

a = [randrange(-100_000, 100_000) for _ in range(100_000)]
 
arr=np.array(a)
 
%timeit task(a)
6.86 ms ± 263 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
 
%timeit arr2=np.hstack((arr[arr<0], arr[arr==0], arr[arr>0]))
1.33 ms ± 6.5 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

from itertools import groupby
from random import randrange
 
 
def cmp(x):
    return (
        1 if x > 0 else
        0 if x == 0 else
        -1
    )
    
def process(list_):
    result = [[] for _ in range(3)]
    for key, group in groupby(list_, key=cmp):
        result[key].extend(group)
    a, b, c = result
    b.extend(a)
    b.extend(c)
    return b
 
def main():
    a = [randrange(-10, 11) for _ in range(10)]
    print(*a)
    result = process(a)
    print(*result)
    
if __name__ == "__main__":
    main()