一、字符串的基本操作

基本操作

msg = "hEllo world!"
print(msg.capitalize())  #首字母大写，后面的小写 Hello world!
print(msg.count('l',3,10))  #查找3到10位有字母'l'的个数；最后一位可以用'-1'表示 2
print(msg.center(20,'*')) #字符串长度为20，居中显示，以'*'填充空格 ****hello world!****
print(msg.swapcase()) #大写全都变成小写,小写变大写
print(msg.endswith('d')) #判断是否以'd'结尾 False
print(msg.index('o')) #返回查找'a'的索引，只返回第一个查到的位置 4
print(msg.find('a',1,9)) #查找'a',找不到返回'-1'  -1
print(msg.isdigit()) #是否整数 False
print(msg.islower()) #是否都是小写
print(msg.isupper()) #是否都大写
print(msg.isalnum()) #是否包含数字
print(msg.isalpha())#是否都是字母组成，不包括空格，其他符号
print(msg.isidentifier())#是否都是字母组成，同上
print(msg.istitle()) #每个单词首字母是否大写
print(msg.isspace()) #是否是空格
print(msg.isprintable()) #字符串中所有字符是否都属于可见字符

msg2="  hello "
print(msg2.lstrip())  #去掉左边的空格，rstrip去掉右边的空格
print(msg2.ljust(10,'*')) #左对齐，右边以'0'填充   hello **
print(msg2.rjust(10,'0')) #右对齐，左边以'0'填充  00  hello
print(msg2.zfill(10)) #用'0'填充，可以用上一种方法表示

msg3="My name is yolanda"
trans=str.maketrans('yolanda','teacher') #注意两个字符串一样长，
print(msg3.translate(trans)) #把句子中对应的字符串都变了 Mt hrme is tearher

 

字符串的format操作

    >>> msg = "my name is {}, and age is {}"
    >>> msg.format("yolanda",18)
    'my name is yolanda, and age is 18'
    >>> msg = "my name is {1}, and age is {0}"
    >>> msg.format("yolanda",18)
    'my name is 18, and age is yolanda'
    >>> msg = "my name is {name}, and age is {age}"
    >>> msg.format(age=18,name="yolanda")
    'my name is yolanda, and age is 18'

 

二、列表

names = ['yolanda','jack','apirl','anni','yolanda','angel']
取值： names[n]

#增加
names.append('tom') #在最后加
print(names)
names.insert(1,'linda') #在索引值为1('jack')的前面插入
print(names)
#删除
names.remove('jack')
print(names)
del names[1]
print(names)
print(names.pop()) #默认删除最后一个并返回
#修改
names[1]='may'
print(names)
#查询
print(names[1:-1])
print(names.index('yolanda')) #取元素的下标,只能取到第一个的下标
first_name=names.index('yolanda')
second_name=names[first_name+1:].index('yolanda')  #第二个相同字符串的下标
print(second_name+first_name+1)
print(names.count('yolanda')) #查询元素的个数

names2=['rain','cat']
names.extend(names2) #合并两个列表
print(names)
names.reverse() #反转
print(names)
names.sort() #按照ASCII排序
print(names)

n2=names 与 n3=names.copy()不同
对names列表进行操作时，n2会与names一同改变，n3不会改变

 列表enumerate的用法

for i in enumerate(names):
    print(i[0],i[1])

for i ,ele in enumerate(names):
    print(i,ele)
结果是相同的
0 yolanda
1 jack
2 apirl
3 anni
4 yolanda
5 angel

 查询数字列表的和：

count=[12,34,43,2,5]
print(sum(count))

列：一个购物车小程序

commodity=[
    ['Iphone',8800],
    ['coffee',50],
    ['shirt',300],
    ['bike',2000]
]
shopping_list=[]
price=[]
while True:
    salary = input("Your salary:")
    if salary.isdigit():
        salary=int(salary)
        break
    else:
        continue
while True:
    print("product list".center(40,"-"))
    for index,i in enumerate(commodity):
        print(index,".",i[0],i[1])
    print("end".center(40, "-"))
    choice=input("What do you want to buy?")
    if choice.isdigit():
        choice=int(choice)
        if choice >=0 and choice < len(commodity):
            p = commodity[choice]
            if salary >= p[1]:
                salary = salary - p[1]
                shopping_list.append(p)
                print("Add \033[32;1m%s\033[0m in shopping list,you have %s" % (p,salary))
            else:
                print("Not much money!You just have %s" %salary)
        else:
            print("no this commodity")
    elif choice == "exit":
        print("You have buy :".center(40,"-"))
        fin = []
        for i in shopping_list:
            fin.append(i[0])
        list = set(fin)
        price = []
        for i in shopping_list:
            price.append(i[1])
        for item in list:
            print(fin.count(item), item)
        print("Thanks for your shopping,you have cost %s"%sum(price))
        exit()
购物车小程序

 给重要字符串添加颜色：



# 各种字体颜色
print("灰白色","\033[29;1m  hello  \033[0m")

print("白色","\033[30;1m  hello  \033[0m")

print("红色","\033[31;1m  hello  \033[0m")

print("黄绿色","\033[32;1m  hello  \033[0m")

print("土黄色","\033[33;1m  hello  \033[0m")

print("蓝色","\033[34;1m  hello  \033[0m")

print("紫色","\033[35;1m  hello  \033[0m")

print("绿色","\033[36;1m  hello  \033[0m")

print("灰色","\033[37;1m  hello  \033[0m")


 












# 各种背景颜色

print("背景黑","\033[40;1m    hello  \033[0m")

print("背景红色：","\033[41;1m    hello  \033[0m")

print("背景黄绿色：","\033[42;1m  hello  \033[0m")

print("背景土黄色：","\033[43;1m  hello  \033[0m")

print("背景蓝色：","\033[44;1m    hello  \033[0m")

print("背景紫色：","\033[45;1m    hello  \033[0m")

print("背景深绿色：","\033[46;1m  hello  \033[0m")

print("背景灰色：","\033[47;1m    hello  \033[0m")