第5课 控制流

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判断语句：if；
循环循环：for, while

1.判断语句 if

a= 10
if a> 10:
    print('a> 10')
elif a== 10:  //`==`是判断符号；`=`是赋值符号
    print('a= 10')
else:
    print('a< 10')


//the result is 
a= 10

2.循环语句 while

while

count= 0
while count< 10:
    count +=1
    print('the sum is: ', count)


//the result is
the sum is:  1
the sum is:  2
the sum is:  3
the sum is:  4
the sum is:  5
the sum is:  6
the sum is:  7
the sum is:  8
the sum is:  9
the sum is:  10

while break

count= 0
while count< 10:
    count +=1
    if count== 5:
        break
    print('the sum is: ', count)

//the result is from 1 to 4
//the result is
the sum is:  1
the sum is:  2
the sum is:  3
the sum is:  4

while continue

count= 0
while count< 10:
    count +=1
    if count== 5:
        continue
    print(' the sum is: ', count)


//the result doesn't include the number 5
//the result is 
 the sum is:  1
 the sum is:  2
 the sum is:  3
 the sum is:  4
 the sum is:  6
 the sum is:  7
 the sum is:  8
 the sum is:  9
 the sum is:  10

3.循环语句 for

Int

for i in range(10):
    print(i)

// the result is 
0
1
2
3
4
5
6
7
8
9

List

a= ['a', 'b', 'c']
for i in a:
    print(i)

// the result is 
a
b
c

Dict

dict= {
    'a': 1,
    'b': 2,
    'c': 'abc'
}
for k,v in dict.items():
    print(k,v)

// the result is 
a 1
b 2
c abc