day02 基础&运算符

2024-01-20 20:07:16

1.循环语句

if-else

score = input('请输入成绩：')
score_int = int(score)

if score_int >= 90:
    print('A')
elif score_int >= 80:
    print('B')
elif score_int >= 70:
    print('C')
else:
    print('D')

if判断嵌套+多行注释

message = '''欢迎致电10086
1.话费查询：
2.流量服务：
3.业务办理：
4.人工服务：'''
print(message)

index = input('请输入你要选择的业务：')
index = int(index)
if index == 1:
    print('话费查询')
elif index == 2:
    print('流量服务')
elif index == 3:
    content = '''业务办理
    1.修改密码：
    2.更改套餐：
    3.停机：'''
    print(content)
    value = input('请输入要办理的业务：')
    value = int(value)
    if value == 1:
        print('修改密码')
    elif value == 2:
        print('更改套餐')
    elif value == 3:
        print('停机')
    else:
        print('错误')
elif index == 4:
    print('人工服务')
else:
    print('输入错误')

while循环

while True:
    print('人生苦短，我用Python.')
    
while 1>0 and 2>1:
    print('人生苦短，我用Python。')

请通过循环，将count每次循环都+1

count = 1
while True:
    count = count + 2
    print(count)
    
#练习
while True:
    count = 1
    print(count)
    count = count + 1

请通过循环，打1，2，3，4，... 10

count = 1
while count <= 10:
     print(count)
     count = count + 1

请通过循环，打印1，2，3，4，5，6，8，9，10

#错误示例
count = 1
while count <= 10 and count != 7:
    print(count)
    count = count + 1

#正确
count = 1
while count <= 10:
    if count != 7:
        print(count)
    count = count + 1

#正确
count = 1
while count <= 10:
    if count == 7:
        pass
    else:
        print(count)
    count = count + 1

break

while True:
    print(666)
    break #终止当前循环
print('结束')

#练习：通过break实现打印 1-10
'''
count = 1
while True:
    print(count)
    if count == 10:
        break
    count = count + 1
print('结束')
'''
'''
#break 终止当前循环
while True:
    print('你好')
    while True:
        print('666')
        break
    break
'''

continue

'''
count = 1
while count <= 10:
    print(count)
    continue #本次循环如果遇到continue,则不再继续往下走，而是回到循环条件位置，
    count = count + 1
'''

#示例： 1 2 3 4 5 6 8 9 10
'''
count = 1
while count <= 10:
    if count == 7:
        count = count + 1
        continue
    print(count)
    count = count + 1
'''

while else

'''
count = 1
while count < 10:
    print(count)
    count = count + 1
else:   #不再满足while后的条件时，触发。 或 条件= False
    print('ELSE代码块')
print('结束')
'''
count = 1
while True:
    print(count)
    if count == 10:
        break
    count = count + 1
else:   #不再满足while后的条件时，触发。 或 条件= False
    print('ELSE代码块')
print('结束')

总结

while基本结构
break
continue
while else

2.字符串格式化

#字符串格式化存在的意义
'''
name = input('姓名：')
do = input('在干什么：')

template = "%s在教室,%s。"%(name,do,)
print(template)
'''

#直接做占位符
# template = '我是%s,年龄%s,职业%s.'%('alex',73,'讲鸡汤',)
# print(template)

# name = 'alex'
# template = '%s现在手机的电量是100%%'%(name,)
# print(template)

#练习
name = input('请输入姓名：')
age = input('请输入年龄：')
job = input('请输入职业：')
hobby = input('请输入爱好：')
msg = '''
---------- info of Alex Li ----------
Name  : %s
Age   : %s
job   : %s
Hobbie: %s
---------- end ----------'''
data = msg %(name,age,job,hobby,)
print(data)

3.运算符

#算术运算符
# value = 11 % 3
# print(value)

#练习题：通过循环打印1-100中的奇数

# count = 1
# while count <= 100:
#    val = count % 2
#    if val == 1:
#        print(count)
#     count = count + 1

# val = 2 ** 8
# print(val)

# val = 9/2
# print(val)

# val = 9//2
# print(val)

#练习题：打印1~100之间相加
'''
total = 0
count = 1
while count <= 100:
    total = total + count
    count = count + 1
print(total)
'''


total = 0
# total1 = 0
# total2 = 0
'''
count = 1
while count <= 100:
    val = count % 2
    if val == 1:
        total1 = total - count
    else:
        total2 = total + count
    count = count + 1
total = total1 + total2
print(total)
'''

#逻辑运算符 and or not
#一般情况下
# if 1>0 or 1>2:
#     print('666')

# c+=a 等效于c=c+a

#二般情况
##小知识
# - int
# - str
# - bool

# v1 = '666'
# v2 = int(v1)

#数字转布尔值
# v1 = 0
# v2 = bool(v1)
# print(v2)

#字符串转布尔值
# v1 = '0'
# v2 = bool(v1)
# print(v2)

#布尔值转换其他
# v1 = True
# v2 = int(v1)
# print(v2)

# v1 = True
# v2 = str(v1)
# print(v2)

#转换
'''
    - 字符串转数字
    - 数字转字符串
    - “”、0 转换布尔值之后是False，其余是True
'''

#对于or，如果有遇到
'''
    value = 1 or 9
    第一个值如果转换成布尔值是真则等于第一个值
    第一个值如果转换成布尔值是假则等于第二个值
    如果有多个or条件，则从左到右依次进行上述的流程
    示例：
        v1 = 0 or 1
        v2 = 8 or 10
        v3 = 0 or 9 or 8
'''
# value = 0 or 9
# print(value)

# value = 1 or 9
# print(value)

# value = 0 or ''
# print('--->',value,'<-----')

#对于and ，如果遇到
'''
  如果第一个值转换成布尔值是True，则value=第二个值  
  如果第一个值转换成布尔值是False，则value=第一个值  
  如果有多个and条件，则从左到右依次进行上述流程
  示例：
    v1 = 1 and 9
    v2 = 1 and 0
    v3 = 0 and 7
    v4 = 0 and ''
    v5 = 1 and 0 and 9  
'''
# v1 = 1 and 9
# print(v1)

# v2 = 1 and 0
# print(v1)

# v3 = 0 and 7
# print(v3)

# v4 = 0 and ''
# print(v4)

# v5 = 1 and 0 and 9
# print(v5)

#综合
#先看and再看or
# v1 = 1 and 9 or 0 and 6

4.编码

编码扩展
- ascii
- unicode
  - ecs2
  - ecs4
- utf-8 ,中文用3个字节
- utf-16
- gbk，中文用2个字节
- gb2312，中文用2个字节
单位
- 8bit = 1byte
- 1024byte = 1KB
- 1024KB = 1MB
- 1024MB = 1KB
- 1024KB = 1GB
- 1024GB = 1TB
- 1024TB = 1PB

码农公寓

1.循环语句

2.字符串格式化

3.运算符

4.编码

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