知識點：

# name.remove(element) #刪除
# del name[2] #刪除
# del name #刪除列表
# name.clear() #清空列表
# name.extend() #擴展

name1=["a1","a2"]
name2=["b1","b2"]
print(name1+name2)  #擴展
name1.extend(name2) #擴展
print(name1)

name2.reverse() #反轉
print(name2)
name2.sort()
print(name2)

name3=["a","v","2","3"]
name3.sort()  #排序
print(name3) #字符排序用ascii表的順序排，python3是字符與數字無法排
name1.clear() #清空內容
print(name1)

布爾分布

條件成立 true

條件不成立，false

字符串常用功能：

name = "\n\t   jensen xie   \t"

print(name)

print(name.strip()) #脫掉，把前後的空格，\t\n脫掉

print(name.split()) #分割，把一個字符默認按空格分割為列表類型



name = "\n\t   jensen xie;alex li   \t"

print(name.split(";")) #分割，把一個字符默認按空格分割為列表類型，可以指定分隔符



print(len(name)) # 長度

name1="jensen,zhicong,lizhi"

 
print(name1.index("h")) # 索引

# 只提取字符串中一部分信息，叫切片

print(name1[0:6])

print(name1[7:14])

print(name1[-5:])

print(name1[0::2]) #2是切的步長
print(name1[0::1]) #2是切的步長

替換

name = ["a","b","c","d","e"]
print(name)
print(name.index("d"))
name[name.index("d")]="dd"
print(name)

name = [] #列表
print(name)
print(type(name))

name = ["

--------------------------------------------------------------

# 作業購物車
# 1、啟動程序後，讓用戶輸入工資，然後打印商品列表
# 2、允許用戶根據商品編號購買商品
# 3、用戶選擇商品後，檢測余額是否夠，夠就直接扣款，不夠就提醒
# 4、可隨時退出，退出時，打印已購買商品和余額

number=[1,2,3,4,5]
goods=["魚","手機","米","平板","電視"]
price=[30,6000,15,3000,4000]

wages=input("請輸入你的預算：")

for i in range(0,5):
print(number[i],"、商品：",goods[i],"，價格：",price[i],"元")

buy1=[]
buy=[0,0,0,0,0]
goods1=[0,0,0,0,0]

buy1=input("要買商品的編號，用‘,‘隔開:")

a1=len(buy1)
print(a1)

for j in range(9):
t1 = 2 * j + 1
if t1 <= a1:
buy[j]=int(buy1[2*j])
else:
break

print(buy)

account=0

for j in range(5):
if buy[j]>0:
account=account+price[buy[j]-1]
goods1[j]=goods[buy[j]-1]
else:
break

print(account)
print(wages)
print(type(account),type(wages)) #兩個數字的類型不一樣，無法比較

if int(wages) < account :
print("余額不足，你的預算是：",wages,"你將支付：",account)
else:
order="感謝購買！以下是你的訂單："
for j in range(5):
if str(goods1[j]) !="0":
order=order+str(goods1[j])+","
else:
break
print(order,"余額為：",int(wages)-account)

# 編寫登陸接口
# ? 輸入用戶名密碼
# ? 認證成功後顯示歡迎信息
# ? 輸錯三次後鎖定

name = "jensen"
passwd = "123"

for i in range(4):
name1 = input("your name:")
passwd1 = input("your passwd:")

if name1 == name and passwd1 == passwd :
print("認證成功後顯示歡迎信息")
break
else :
if i+1<3:
print("請重新輸入。")
i+=1
continue
else:
print("輸錯三次後鎖定")
break

購物車與登錄小習題