Python笔记day04（基础）

1，昨日内容及作业讲解

ascii：字母，数字，特殊字符：1个字节，8位
Unicode：16位两个字节升级 32 位四个字节
utf-8：最少一个字节 8位表示。英文字母 8位 1个字节
欧洲16位，2个字节
中文24位，3个字节
gbk：中文2个字节，英文字母1个字节。

    int：bit_lenth()
      bool:True False
      str: str --->bool :bool(str):  ''--->False
      str:
      s = 'alexsb'
      s1 = s[1]
      s2 = s[1:3]
      s3 = s[0:]  s[:]
      s4 = s[0:-1]
      s5 = s[0:3:2]
      s6 = s[2::-2]

captlze首字母大写
upper()全大写
lower()全小写
find通过元素找索引，找不到-1
index()通过元素找索引，找不到报错
swpcase 大小写翻转

repalce(old,new,count)
isdigit() 返回bool值
isapha()
isnumpha()
startswith endswith
title 首字母大写
center（）居中
strip（）lstrip rstrip
split
format 格式化输出
{}
{0}{1}{2}{0}
{name}{age}{hobby} name= age+ hobby

len() 长度
count 计数

for i in 可迭代对象：
pass

2，列表

增删改查
列表的循环
列表的嵌套

# li = ['alex',[1,2,3],'wusir','egon','女神','taibai']
# l1 = li[0]
# print(l1)
# l2 = li[1]
# print(l2)
# l3 = li[0:3]
# print(l3)

li = ['alex','wusir','egon','女神','taibai']

增加 append insert

# li.append('日天')
# li.append(1)
# print(li)
# while 1:
#     username = input('>>>')
#     if username.strip().upper() == 'Q':
#         break
#     else:
#         li.append(username)
# print(li)
# li.insert(4,'春哥')
# print(li)
# li.extend('二哥')
# li.extend([1,2,3])
# print(li)

删

li = ['taibai','alex','wusir','egon','女神',]
# name = li.pop(1)  # 返回值
# name = li.pop()  # 默认删除最后一个
# print(name,li)

# li.remove('taibai')  # 按元素去删除
# print(li)

# li.clear()  # 清空
# print(li)

# del li
# del li[0:2]  # 切片去删除
# print(li)

改

# li[0] = '男兽'
# li[0] = [1,2,3]
#切片
# li[0:3] = '云姐plfdslkmgdfjglk'
# li[0:3] = [1,2,3,'春哥','咸鱼哥']
# print(li)

查

# for i in li:
#     print(i)
# print(li[0:2])

公共方法：

# l = len(li)
# print(l)
# num = li.count('taibai')
# print(num)
# print(li.index('wusir'))
# li = [1,5,4,7,6,2,3]
# #正向排序
# # li.sort()
# # print(li)
# #反向排序
# # li.sort(reverse=True)
# # print(li)
# #反转
# li.reverse()
# print(li)

列表的嵌套

# print(li[1][1])
# name = li[0].capitalize()
# # print(name)
# li[0] = name
# li[0] = li[0].capitalize()
# li[2] = '苑日天'
# print(li[2].replace('昊','ritian'))
# li[2] = li[2].replace('昊','ritian')
# li[3][0] = li[3][0].upper()
# print(li)

3，元祖

元祖只读列表，可循环查询，可切片。儿子不能改，孙子可能可以改。

# tu = (1,2,3,'alex',[2,3,4,'taibai'],'egon')
# # print(tu[3])
# # print(tu[0:4])
# # for i in tu:
# #     print(i)
# tu[4][3]=tu[4][3].upper()
# print(tu)
# tu[4].append('sb')
# print(tu)

# s = 'alex'
# s1 = 'sb'.join(s)
# print(s1)

列表转化成字符串 list —–> str join

# li = ['taibai','alex','wusir','egon','女神',]
# s = '++++'.join(li)
#str ----->list   split()
# print(s)

range [1,2,3,4,5,6,…….100……..]

# for i in range(3,10):
#     print(i)
# for i in range(10):
#     print(i)
# for i in range(0,10,3):
#     print(i)
# for i in range(10,0,-2):
#     print(i)
# for i in range(10,-1,-2):
#     print(i)

li = [1,2,3,5,'alex',[2,3,4,5,'taibai'],'afds']
# for i in li:
#     if type(i) == list:
#         for k in i:
#             print(k)
#     else:print(i)

for i in range(len(li)):
    if type(li[i]) == list:
        for j in li[i]:
            print(j)
    else:print(li[i])

4，作业

# s = '132a4b5c'
# s1 = s[0]+s[2]+s[1]
# print(s1)
#使用while和for循环分别打印字符串s=’asdfer’中每个元素。
s = 'fkld'
# for i in s:
#     print(i)
# index = 0
# while 1:
#     print(s[index])
#     index += 1
#     if index == len(s):break
#如：content = input(‘请输入内容:’)  # 如用户输入：5+9或5+ 9或5 + 9，然后进行分割再进行计算。
# content=input('>>>').strip()
# con1=content.split('+')
#li[]
# num=0
# for i in con1:
#     num+=int(i)
# print(num)
# content=input('>>>').strip()
# index = content.find("+")
# a = int(content[0:index])
# b = int(content[index+1:])
# print(a + b)
#咱们任意输入一串文字+数字 统计出来数字的个数

s = input("请输入：")  # '1234324324fdsaf1fdsaf12'
count = 0
for i in s:
    if i.isdigit():
        count += 1
print(count)