参考资料：
【Python教程】《零基础入门学习Python》最新版（2022年12月26日更新）

分支结构

1. if结构

1
2
3
if condition:
    statement_1(s1)
statement_2(s2)

2. if-else结构

1
2
3
4
5
if condition:
    statement_1(s1)
else:
    statement_2(s2)
statement_3(s3)

3. if-elif-elif…(-else)结构

1
2
3
4
5
6
7
if condition_1:
    statement_1(s1)
elif condition_2:
    statement_2(s2)
...
# else:
#     statement_n(sn)

4. oneline结构

1
true_statement if condition else false_statement

循环结构

1. while循环

1.1 基本结构

1
2
3
while condition:
    statement_1(s1)
statement_2(s2)

1.2 while-break结构

1
2
3
4
5
6
while condition_1:
    statement_1(s1)
    if condition_2:
        break
    statement_2(s2)
statement_3(s3)

1.3 while-else结构

1
2
3
4
5
6
7
8
while condtion_1:
    statement_1(s1)
    if condition_2:
        break
    statment_2(s2)
else:
    statment_3(s3)
statement_4(s4)

仅在循环由condition_1退出时才执行else，由break终止则不执行else

1.4 嵌套结构

1
2
3
4
5
6
7
8
i = 1
while i <= 9:
    j = 1
    while j <= i:
        print(j, "*", i, "=", j*i, end=" ")
        j += 1
    print()
    i += 1
1
2
3
4
5
6
7
8
9
1 * 1 = 1 
1 * 2 = 2 2 * 2 = 4 
1 * 3 = 3 2 * 3 = 6 3 * 3 = 9 
1 * 4 = 4 2 * 4 = 8 3 * 4 = 12 4 * 4 = 16 
1 * 5 = 5 2 * 5 = 10 3 * 5 = 15 4 * 5 = 20 5 * 5 = 25 
1 * 6 = 6 2 * 6 = 12 3 * 6 = 18 4 * 6 = 24 5 * 6 = 30 6 * 6 = 36 
1 * 7 = 7 2 * 7 = 14 3 * 7 = 21 4 * 7 = 28 5 * 7 = 35 6 * 7 = 42 7 * 7 = 49 
1 * 8 = 8 2 * 8 = 16 3 * 8 = 24 4 * 8 = 32 5 * 8 = 40 6 * 8 = 48 7 * 8 = 56 8 * 8 = 64 
1 * 9 = 9 2 * 9 = 18 3 * 9 = 27 4 * 9 = 36 5 * 9 = 45 6 * 9 = 54 7 * 9 = 63 8 * 9 = 72 9 * 9 = 81

2. for循环

2.1 基本结构

1
2
3
for identifier in iterable
    statement_1(s1)
statement_2(s2)

Translation:
identifier: 标识符（变量名）
iterable: 可迭代对象 

1
2
3
4
5
sum = 0
for i in range(10):
    sum += i
print(sum)
# 45

2.2 range()函数

range(stop)
range(start, stop)
range(start, stop, step) 

1
2
3
4
5
6
7
for n in range(2, 10):
    for m in range(2, n):
            if n % m == 0:
                print(n, "=", m, "*", n // m)
                break
    else:
        print(n, "is a prime number")
1
2
3
4
5
6
7
8
2 is a prime number
3 is a prime number
4 = 2 * 2
5 is a prime number
6 = 2 * 3
7 is a prime number
8 = 2 * 4
9 = 3 * 3