Day1 python基础1

 一、Hello World 

print("Hello World!")

 二、变量以及字符编码 

变量名只能是字母，数字，下划线，且第一个不能是数字
以下关键字不能声明为变量名
['and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else',
'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is',
'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'with', 'yield']

 1 name = "Zhang wb"
 2 name2 = name
 3 print("my name is",name,name2)  
 4 
 5 name = "Sha Shan"
 6 gf_of_oldboy = "Rlongyi"
 7 
 8 PIE = "常量"
 9 
10 print(name,name2)

 

ASCII 255 1B,GB2312 7XXX汉字,GBK 2xxxx汉字,GB18030 27000汉字  向下兼容
Unicode万国码 2B
UTF-8可变长，英文-ascii 1B，中文-utf8 3B

 三、注释 

单行注释  #注释内容

多行注释  ‘’‘注释内容’‘’或“”“注释内容”“”

 四、输入 

username=input("username:")
password=input("password:")
print(username,password)

需注意input的结果是字符串
输入密码时不可见，可利用getpass

import  getpass
#pycharm不好用
password = getpass.getpass("password:")

不同形式的输入

name=input("name:")
age=int(input("age:"))
job=input("job:")
info = '''
--------- info of %s ----
Name:%s
Age:%d
Job:%s
'''%(name,name,age,job)
print(info)

%s 字符串，%d，整数，%f，浮点数

name=input("name:")
age=int(input("age:"))
job=input("job:")
info2 = '''
   --------- info of {_name}----
Name:{_name}
Age:{_age}
Job:{_job}
'''.format(_name=name,_age=age,_job=job)
print(info2)

name=input("name:")
age=int(input("age:"))
job=input("job:")
info3 = '''
          --------- info of {0}----
Name:{0}
Age:{1}
Job:{2}
'''.format(name,age,job)
print(info3)

 五、if...else... 

猜年龄

age = 56

guess_age = int(input("guess age:"))

if guess_age == age :
    print("yes,you get it")
elif guess_age > age :
    print("think smaller...")
else:
    print("thinker bigger...")

 六、while 

while死循环

count = 0
while True:
    print("count:",count)
    count+=1

利用while实现只有三次机会的猜年龄

count = 0
while count < 3:
    guess_age = int(input("guess age:"))
    if guess_age == age:
        print("yes,you get it")
        break
    elif guess_age > age:
        print("think smaller...")
    else:
        print("thinker bigger...")
    count+=1
else:
    print("you have tried too many times...")
#循环正常走完，执行else，break的话不执行else

 七、for 

利用for输出0--9

for i in range(10):
    print("loop",i)
print("")

利用for输出5到9的奇数

for i in range(5,10,2):
    print("loop", i)

利用for实现只有三次机会的猜年龄

age = 56

for count in range(3):
    guess_age = int(input("guess age:"))
    if guess_age == age:
        print("yes,you get it")
        break
    elif guess_age > age:
        print("think smaller...")
    else:
        print("thinker bigger...")

else:
    print("you have tried too many times...")

猜年龄任意玩

age = 56
count = 0
while count < 3 :
    guess_age = int(input("guess age:"))
    if guess_age == age:
        print("yes,you get it")
        break
    elif guess_age > age:
        print("think smaller...")
       # print(count)
    else:
        print("thinker bigger...")
    count+=1
    if count == 3:
        countinue_confirm = input("do you want to keep guessing..?(y/n)")
        if countinue_confirm != 'n' :
            count = 0