老男孩python第一天笔记
1、变量 把结果存下来,变量存在内存里,name1 = "hepeng" name2=name1 name1 = "hp" print(name1,name2)
name2是name1在内存中的指向相当于软连接,输出结果,name1=hp name2=hepeng
2、字符编码都是向下兼容的,unicode万国码,utf8 存英文1byte 存中文3byte
3、用户交互程序,username = input("请输入")
变量引用格式化输出,%s字符串,%d只能接受数字,%f浮点小数
name = hp info= "Name:%s" % (name) print(info)
字符串转 整形 int 整形转字符串str
用format格式化 输出
name = "hp" info2 = "Name:{_name}".format(_name = name) print(info2)
4、密码密文使用getpass
import getpass
password = getpass.getpass("password:") getpass 在pycharm里不好使,在命令行可以
5、if else循环,用户名密码匹配输出ok,不匹配输出wrong
if username == user and password = pwd : print("ok") else: print("wrong")
6、while循环,年龄猜三次,正确就退出,三次不对给提示
count = 0 age = 23 while count <3: guess_age = int(input("guess age")) if guess_age == age: print("you got it") break elif guess_age > age: print("too bigger") else: print("too smaller") count +=1 else: print("you have try too many choice")
7、for 循环
等同上边while代码,用for循环实现age猜三次
age = 23 for i in range(3): guess_age = int(input("guess age")) if guess_age == age: print("you got it") break elif guess_age > age: print("too bigger") else: print("too smaller") else: print("you have try too many choice")
for i in range(0,10,3) 0-10隔三个
8、continue跳出本次循环进入下一次循环,break结束整个循环
for i in range(10): if i < 3: print("loop",i) else: continue print("hehe")
当i循环到3的时候就不执行print了,continue直接跳出本次循环进行下次循环
for i in range(10): if i < 3: print("loop",i) else: break print("hehe")
当i循环到3的时候直接跳出循环,不在执行,两个的输出结果是一样的,但是原理不同