字符串,列表,元组

字符串,列表,元组, 练习:

#判断120是否在对象s列表当中
s = ["zhiqiao","lingyan",["yan"],520]
i = 120 in s
print(i)
False
#修改列表
s = ["zhiqiao","qiao",["yan"],12]
i = s[2] = "ling","yan"    #通过索引的方式进行修改和添加第二与第三个元素为ling,yan
for i in s:
    print(i)

#删除列表del
s = ["zhiqiao","qiao",["yan"],12]
del s[1]    #删除列表第一个元素"qiao"
print(s)

##字符串可以转换为列表,列表可以转换为元组, 反过来也都一样
##若想修改元组,必须得先装换成元组或者字符串,因为元组当中的元素不可被修改
#将列表转换为元组或字符串
s = ["zhiqiao","qiao",["yan"],12]
print(tuple(s),str(s))

#字符串,元组,列表只要不带数字都可以用join连接. 第一个元素被系统占用自动从第二个元素开始

连接
st = "zhi","ling"
li = ["zhiqiao","lingyan",  "520"]
tu = ("qiao","yan",)    #建议元组末尾加逗号来表示元组,以免与其他参数弄混淆
v = "_hello_".join(li)+"","".join(tu)+"","".join(st) #可多次使用join结合字符串,与数据库

的join用法一样
print(v)