In [2]:
#快速排序
def quicksort(arr):
if len(arr) <= 1:
return arr
pivot = arr[len(arr) // 2]
left = [x for x in arr if x < pivot]
middle = [x for x in arr if x == pivot]
right = [x for x in arr if x > pivot]
return quicksort(left) + middle + quicksort(right)
print(quicksort([3,6,9,10,8,2,7,1,5,1,4,8]))
In [3]:
#带index的枚举,以及%来format
animals = ['cat', 'dog', 'monkey']
for idx, animal in enumerate(animals):
print('#%d: %s' % (idx+1, animal))
In [4]:
#列表推导
nums = [0, 1, 2, 3, 4]
even_squares = [x ** 2 for x in nums if x % 2 == 0]
print(even_squares)
In [7]:
#Numpy Array
#numpy array是一组网格化的数据,这些数据的类型完全相同(不同于Python自带的list),并且被非0整数作为索引。有两个属性。
#dimension维度,描述了array的级数。
#shape描述了给定维度下的数组形状。
import numpy as np
a = np.array([1,2,3])
print(type(a))
print(a.shape)
print(a.ndim)