day1-字符串拼接、表達式、break和continue
阿新 • • 發佈:2017-12-26
int pre small think range span guess mat lex
一 字符串拼接方式
1. 用加號(+)拼接
name = ‘eason‘ age = 18 info = ‘‘‘---info:‘‘‘+ name +‘‘‘ age: ‘‘‘ + str(age) print(info)
2. 用占位符(%)拼接
name = "eason" age = 18 info = ‘‘‘-----info----- name: %s age: %d ‘‘‘ % (name,age) print(info)
3. 用format方法拼接
1.關鍵字拼接(官方推薦) name = "eason01" age = 19 info = ‘‘‘-----info---- name: {_name} age:: {_age}‘‘‘.format(_name = name,_age = age) print(info) 2.占位符拼接 name = "eason02" age = 20 info = ‘‘‘-----info----- name: {0} age: {1} ‘‘‘.format(name,age) print(info)
二 表達式if...else...
場景一:用戶登錄驗證
name = input("請輸入用戶名:") pwd = input("請輸入密碼:") if name == "alex" and pwd == "cmd": print("歡迎,alex!") else: print("用戶名密碼錯誤!")
場景二:猜年齡遊戲
age_of_oldboy = 22 guess_age = int(input("guess age:")) if guess_age == age_of_oldboy: print("yes,you got it !") elif guess_age < age_of_oldboy: print("think bigger!") else: print("think smaller!")
三 表達式for loop
最簡單的循環10次
for i in range(10): print("loop:", i )
需求一,遇到小於5的循環次數就不走了,直接進入下一次循環
for i in range(0,10,2): #0 初始化值,10 序列長度, 2 步長 if i < 5: continue #不往下走了,直接進入下一次loop print("loop",i)
需求二,遇到大於5的循環次數就不走了,直接退出
for i in range(10): #默認初始化值 0 ,步長為 1 if i > 5: break # 不往下走了,直接跳出當前整個loop print("loop",i)
四 表達式while
count = 0 while True: print("11111",count) count += 1 if count == 100: print("2222") break
如何實現讓用戶不斷的猜年齡,但只給最多3次機會,再猜不對就退出程序
my_age = 25 count = 0 while count < 3: user_input = int(input("input your guess num:")) if user_input == my_age: print("you got it!") break elif user_input < my_age: print("think bigger!") else: print("think smaller!") count += 1 else: print("you have tied too many times...")
註:當遇到不正常退出(break)時,則程序不執行循環(for,while)所對應的else下的代碼,只有當for循環體中代碼正常執行的時,才執行else中的代碼
更多python資料:猛擊這裏
day1-字符串拼接、表達式、break和continue