delta = datetime.now() - startprint"The last 2 elements of the sum", c[-2:]print"PythonSum elapsed time in microseconds", delta.microseconds start = datetime.now() c = numpysum(size) delta = datetime.now() - startprint"The last 2 elements of the sum", c[-2:]print"NumPySum elap...
import numpy as np arr = np.array([1, 2, 3, 4, 5]) # 提取第一个元素 first_element = arr[0] print(first_element) # 输出: 1 # 提取最后一个元素 last_element = arr[-1] print(last_element) # 输出: 5 # 提取多个元素 multiple_elements = arr[[0, 2, 4]] print(multiple_element...
27, 64]) >>> # equivalent to a[0:6:2] = 1000; >>> # from start to position 6, exclusive, set every 2nd element to 1000 >>> a[:6:2] = 1000 >>> a array([1000, 1, 1000, 27, 1000, 125, 216, 343, 512,
7, 8, 9]) print(array1d[4:]) # From index 4 to last index print(array1d[:4]) # From index 0 to 4 index print(array1d[4:7]) # From index 4(included) up to index 7(excluded) print(array1d[:-1]) # Excluded last element print(array1d[:-2]) # Up to second last index(...
pop() # Remove and return the last element of the list print(x, xs) # Prints "bar [3, 1, 'foo']" 你可以在文档中查阅列表的细节。 切片Slicing:除了一次访问一个列表元素外,Python还提供了简洁的语法来访问子列表,这就是切片。 nums = list(range(5)) # range is a built-in function that...
prints "2"xs[2] ='foo'# Lists can contain elements of different typesprintxs# Prints "[3, 1, 'foo']"xs.append('bar')# Add a new element to the end of the listprintxs# Printsx = xs.pop()# Remove and return the last element of the listprintx, xs# Prints "bar [3, 1, '...
dimensions in the array. For two dimensions, we’d use int[:,:]; for three, we’d use int[:,:,:].We also should indicate the memory layout for the array. By default in NumPy and Cython, arrays are laid out in a contiguous fashion compatible with C. ::1 is our last element in...
Example Print the last element from the 2nd dim: import numpy as nparr = np.array([[1,2,3,4,5], [6,7,8,9,10]]) print('Last element from 2nd dim: ', arr[1, -1]) Try it Yourself » Exercise? Consider the following code:import numpy as nparr = np.array([[[1, 2],...
[2]='foo'# Lists can contain elements of different typesprint(xs)# Prints "[3, 1, 'foo']"xs.append('bar')# Add a new element to the end of the listprint(xs)# Prints "[3, 1, 'foo', 'bar']"x=xs.pop()# Remove and return the last element of the listprint(x,xs)# ...
Second element: 19.1299991607666 Second last element: 78.56999969482422 1. 2. 3. 4. 5. 6. 查看多个元素 >>> print(Open_array[2:5]) # 第3个到第5个 [19.09000015 18.63999939 18.04999924] >>> print(Open_array[:-5]) # 从开始到最后第4个 ...