3.4. Array Create Recap — Python
3.4.1. SetUp
3.4.2. Recap
>>> a = np.array([1, 2, 3]) >>> b = np.array(range(0, 10)) >>> c = np.arange(0, 10, 2) >>> d = np.linspace(0, 10, 100) >>> e = np.zeros(shape=(2,3)) >>> f = np.zeros_like(a) >>> g = np.ones(shape=(2,3)) >>> h = np.ones_like(a) >>> i = np.empty(shape=(2,3)) >>> j = np.empty_like(a) >>> k = np.full(shape=(2, 2), fill_value=np.nan) >>> l = np.full_like(a, np.nan) >>> m = np.identity(4)
3.4.3. Microbenchmark
>>> # ... %%timeit -r 1000 -n 1000 ... result = np.arange(0, 100, step=2, dtype=float) 651 ns ± 86.5 ns per loop (mean ± std. dev. of 1000 runs, 1000 loops each)
>>> # ... %%timeit -r 1000 -n 1000 ... result = np.array(range(0, 100, 2), dtype=float) 4.38 µs ± 341 ns per loop (mean ± std. dev. of 1000 runs, 1000 loops each)
>>> # ... %%timeit -r 1000 -n 1000 ... result = np.array([x for x in range(0, 100) if x % 2 == 0], dtype=float) 8.25 µs ± 534 ns per loop (mean ± std. dev. of 1000 runs, 1000 loops each)
>>> # ... %%timeit -r 1000 -n 1000 ... result = np.array([float(x) for x in range(0, 100) if x % 2 == 0]) 10.8 µs ± 718 ns per loop (mean ± std. dev. of 1000 runs, 1000 loops each)
>>> # ... %%timeit -r 1000 -n 1000 ... result = np.array([float(x) for x in range(0, 100, 2)]) 6.81 µs ± 443 ns per loop (mean ± std. dev. of 1000 runs, 1000 loops each)
>>> # ... %%timeit -r 1000 -n 1000 ... result = np.array([x for x in range(0, 100, 2)], dtype=float) 4.38 µs ± 349 ns per loop (mean ± std. dev. of 1000 runs, 1000 loops each)