一些算法案例

将数字从小到大排列， （用pycharm中的断点和Debugger来看程序运行的步骤）
def find_smallest(arr):
    smallest = arr[0]
    smallest_index = 0
    for i in range(1,len(arr)):
        if arr[i] < smallest:
            smallest = arr[i]
            smallest_index = i
    return  smallest_index



def selection_sort(arr):
    new_arr = []
    for i in range(len(arr)):
        smallest = find_smallest(arr)
        new_arr.append(arr.pop(smallest))
    return new_arr

print(selection_sort([8,6,4,9,2]))

 用pycharm中的断点和Debugger来看程序运行的步骤

for i in range (1,10):                          九九乘法表 
    for j in range (1,10):
        print('{:2d}*{:2d}={:2d}'.format(i,j,i*j),end=' ')
    print()

i=1然后进入内循环，j=1到9；然后i=2再进入内循环穷举j=1到9，直到i=9进内循环穷举j=1到9

print函数默认换行，是end=' '在起作用，

python默认的print()是换行输出的

print(value, ..., sep=' ', end=' ', file=sys.stdout, flush=False)

In [8]: for i in range(1,9): print(i)
1
2
3
4
5
6
7
8

In [9]: for i in range(1,9):  print(i,end="")
12345678

In [11]: for i in range(9):    print(i,end='$$$')
0$$$1$$$2$$$3$$$4$$$5$$$6$$$7$$$8$$$

In [12]: for i in range(9):    print(i,end='	')
0       1       2       3       4       5       6       7       8