1、變量 ? 把結果存下來,變量存在內存里,name1 = "hepeng" ? ?name2=name1 ? name1 = "hp" ? ?print(name1,name2)
name2是name1在內存中的指向相當于軟連接,輸出結果,name1=hp ?name2=hepeng
2、字符編碼都是向下兼容的,unicode萬國碼,utf8 存英文1byte 存中文3byte
3、用戶交互程序,username = input("請輸入")
變量引用格式化輸出,%s字符串,%d只能接受數字,%f浮點小數
name = hpinfo= "Name:%s" % (name)print(info)
learn python the hard way。 字符串轉 整形 int ?整形轉字符串str
用format格式化 輸出
name = "hp"info2 = "Name:{_name}".format(_name = name)print(info2)
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4、密碼密文使用getpass
python筆記。 import getpass
password = getpass.getpass("password:") ? getpass ?在pycharm里不好使,在命令行可以
5、if else循環,用戶名密碼匹配輸出ok,不匹配輸出wrong
if username == user and password = pwd :print("ok")else:print("wrong")
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6、while循環,年齡猜三次,正確就退出,三次不對給提示
count = 0 age = 23while count <3:guess_age = int(input("guess age"))if guess_age == age:print("you got it")breakelif guess_age > age:print("too bigger")else:print("too smaller")count +=1 else:print("you have try too many choice")
python爬蟲。?
7、for 循環?
等同上邊while代碼,用for循環實現age猜三次
age = 23for i in range(3):guess_age = int(input("guess age"))if guess_age == age:print("you got it")breakelif 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隔三個
8、continue跳出本次循環進入下一次循環,break結束整個循環
for i in range(10):if i < 3:print("loop",i)else:continueprint("hehe")
python有什么用、當i循環到3的時候就不執行print了,continue直接跳出本次循環進行下次循環
for i in range(10):if i < 3:print("loop",i)else:breakprint("hehe")
當i循環到3的時候直接跳出循環,不在執行,兩個的輸出結果是一樣的,但是原理不同
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python3??
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python筆記全??
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