python 常用字符串 列表元祖字典都 自带的函数方法


上节内容回顾和补充

	编程语言
		高级
		低级
		
	Python种类
		JavaPython
		cPython    *****
		pypy
		
		字节码 和 机器码
		
	Python程序:
		1. 
			终端:
				C:\python35\python.exe D:\1.py
			解释器:
				C:\python35\python.exe 
				
		2. 文件形
			#/usr/bin/u/ubv/a python
			
			python 1.py
			
			./1.py      加权限
			
		3. 编码
			#/usr/bin/u/ubv/a python
			# -*- coding:utf-8 -*-
			补充:
				
			字节,位
			unicode   utf8   gbk
			utf8: 3
			gbk : 2
		
		4. print("sdf")
		
		5. inp = input('>>>')
			
			PS:
				>>> hello
				inp = "hello"
				
				
				>>> 10
				inp = "10"
				
				# 如果将字符串转换成数字     new_inp = int(inp)
				
				inp * 10 =????? 
			
			
		6. 变量名
		
			字母
			数字
			下划线
			
			要求:
				不能数字开头
				不能使用关键字
				建议不要用python内置的。。。。
		
		7. 条件语句
			1. 基本
			2. 嵌套
			3. if   elif   else ...
			
		8. while循环
			while 条件:
				....
		
			print('...')
			
			补充:
				a. while else
				b. continue   break
				   continue ,终止当前循环,开始下一次循环
				   break    ,终止所有循环
			
		用户登陆(三次机会重试)
		count = 0
		while count < 3:
			user = input('>>>')
			pwd = input('>>>')
			if user == 'alex' and pwd == '123':
				print('欢迎登陆')
				print('..........')
				break
			else:
				print('用户名或者密码错误')
			count = count + 1
		
今日内容:
	
	python开发IDE: pycharm、eclipse
	
	# 专业版
	# 不要汉化
	
	1、运算符
		结果是值
			算数运算
				a = 10 * 10
			赋值运算
				a = a + 1    a+=1

		结果是布尔值
			比较运算
				a = 1 > 5
			逻辑运算
				a = 1>6 or 1==1
			成员运算
				a = "蚊" in "郑建文"
		
	2、基本数据类型
	
	
		数字  int ,所有的功能,都放在int里
			a1 = 123
			a1 = 456
			
			- int
				将字符串转换为数字
					a = "123"
					print(type(a),a)

					b = int(a)
					print(type(b),b)
					
					num = "0011" 
					v = int(num, base=16)
					print(v)
			- bit_lenght
					# 当前数字的二进制,至少用n位表示
					r = age.bit_length()
			
		字符串  str
					###########################################

					# 1 首字母大写
						# test = "aLex"
						# v = test.capitalize()
						# print(v)

					# 2 所有变小写,casefold更牛逼,很多未知的对相应变小写
						# v1 = test.casefold()
						# print(v1)
						# v2 = test.lower()
						# print(v2)

					# 3 设置宽度,并将内容居中
						# 20 代指总长度
						# *  空白未知填充,一个字符,可有可无
						# v = test.center(20,"中")
						# print(v)

						# test = "alex"
						# v = test.ljust(20,"*")
						# print(v)

						# test = "alex"
						# v = test.rjust(20,"*")
						# print(v)

						# test = "alex"
						# v = test.zfill(20)
						# print(v)


					# 4 去字符串中寻找,寻找子序列的出现次数
						# test = "aLexalexr"
						# v = test.count('ex')
						# print(v)

						# test = "aLexalexr"
						# v = test.count('ex',5,6)
						# print(v)

					# 欠
					# encode
					# decode

					# 5
						# 以什么什么结尾
						# 以什么什么开始
						# test = "alex"
						# v = test.endswith('ex')
						# v = test.startswith('ex')
						# print(v)

					# 6 expandtabs,断句20,
						# test = "username\temail\tpassword\nlaiying\[email protected]\t123\nlaiying\[email protected]\t123\nlaiying\[email protected]\t123"
						# v = test.expandtabs(20)
						# print(v)

					# 7 从开始往后找,找到第一个之后,获取其未知
						# > 或 >=
						# test = "alexalex"
						# 未找到 -1
						# v = test.find('ex')
						# print(v)

					# 8 index找不到,报错   忽略
						# test = "alexalex"
						# v = test.index('8')
						# print(v)


					# 9 格式化,将一个字符串中的占位符替换为指定的值
						# test = 'i am {name}, age {a}'
						# print(test)
						# v = test.format(name='alex',a=19)
						# print(v)

						# test = 'i am {0}, age {1}'
						# print(test)
						# v = test.format('alex',19)
						# print(v)

					# 10 格式化,传入的值 {"name": 'alex', "a": 19}
						# test = 'i am {name}, age {a}'
						# v1 = test.format(name='df',a=10)
						# v2 = test.format_map({"name": 'alex', "a": 19})

					# 11 字符串中是否只包含 字母和数字
						# test = "123"
						# v = test.isalnum()
						# print(v)
						# str
						
					# 12 是否是字母,汉子
						# test = "as2df"
						# v = test.isalpha()
						# print(v)

					# 13 当前输入是否是数字
						# test = "二" # 1,②
						# v1 = test.isdecimal()
						# v2 = test.isdigit()
						# v3 = test.isnumeric()
						# print(v1,v2,v3)


					# 14 是否存在不可显示的字符
						# \t   制表符
						# \n   换行
						# test = "oiuas\tdfkj"
						# v = test.isprintable()
						# print(v)

					# 15 判断是否全部是空格
						# test = ""
						# v = test.isspace()
						# print(v)

					# 16 判断是否是标题
						# test = "Return True if all cased characters in S are uppercase and there is"
						# v1 = test.istitle()
						# print(v1)
						# v2 = test.title()
						# print(v2)
						# v3 = v2.istitle()
						# print(v3)

					# 17 ***** 将字符串中的每一个元素按照指定分隔符进行拼接
						# test = "你是风儿我是沙"
						# print(test)
						# # t = ' '
						# v = "_".join(test)
						# print(v)

					# 18 判断是否全部是大小写 和 转换为大小写
						# test = "Alex"
						# v1 = test.islower()
						# v2 = test.lower()
						# print(v1, v2)

						# v1 = test.isupper()
						# v2 = test.upper()
						# print(v1,v2)
					# 19
						# 移除指定字符串
						# 有限最多匹配
						# test = "xa"
						# # v = test.lstrip('xa')
						# v = test.rstrip('9lexxexa')
						# # v = test.strip('xa')
						# print(v)

						# test.lstrip()
						# test.rstrip()
						# test.strip()
						# 去除左右空白
						# v = test.lstrip()
						# v = test.rstrip()
						# v = test.strip()
						# print(v)
						# print(test)
						# 去除\t \n
						# v = test.lstrip()
						# v = test.rstrip()
						# v = test.strip()
						# print(v)

					# 20 对应关系替换
						# test =  "aeiou"
						# test1 = "12345"

						# v = "asidufkasd;fiuadkf;adfkjalsdjf"
						# m = str.maketrans("aeiou", "12345")
						# new_v = v.translate(m)
						# print(new_v)

					# 21 分割为三部分
						# test = "testasdsddfg"
						# v = test.partition('s')
						# print(v)
						# v = test.rpartition('s')
						# print(v)

					# 22 分割为指定个数
						# v = test.split('s',2)
						# print(v)
						# test.rsplit()


					# 23 分割,只能根据,true,false:是否保留换行
						# test = "asdfadfasdf\nasdfasdf\nadfasdf"
						# v = test.splitlines(False)
						# print(v)

					#  24 以xxx开头,以xx结尾
						# test = "backend 1.1.1.1"
						# v = test.startswith('a')
						# print(v)
						# test.endswith('a)

					# 25 大小写转换
						# test = "aLex"
						# v = test.swapcase()
						# print(v)

					# 26 字母,数字,下划线 : 标识符 def  class
						# a = "def"
						# v = a.isidentifier()
						# print(v)


					# 27 将指定字符串替换为指定字符串
						# test = "alexalexalex"
						# v = test.replace("ex",'bbb')
						# print(v)
						# v = test.replace("ex",'bbb',2)
						# print(v)
					###################### 7个基本魔法 ######################
					# join       # '_'.join("asdfasdf")
					# split
					# find
					# strip
					# upper
					# lower
					# replace
					###################### 4个灰魔法 ######################
					# test = "郑建文妹子有种冲我来"

					# 一、for循环
						# for 变量名 in 字符串:
						#     变量名
						# break
						# continue
						
						
						# index = 0
						# while index < len(test):
						#     v = test[index]
						#     print(v)
						#
						#     index += 1
						# print('=======')

						# for zjw in test:
						#     print(zjw)

						# test = "郑建文妹子有种冲我来"
						# for item in test:
						#     print(item)
						#     break

						# for item in test:
						#     continue
						#     print(item)

					# 二、索引,下标,获取字符串中的某一个字符
						# v = test[3]
						# print(v)

					# 三、切片
						# v = test[0:-1] # 0=<  <1
						# print(v)

					# 四、获取长度
						# Python3: len获取当前字符串中由几个字符组成
						# v = len(test)
						# print(v)

					# 注意:
					# len("asdf")
					# for循环
					# 索引
					# 切片

					# 五、获取连续或不连续的数字,
						# Python2中直接创建在内容中
						# python3中只有for循环时,才一个一个创建
						# r1 = range(10)
						# r2 = range(1,10)
						# r3 = range(1,10,2)
						# 帮助创建连续的数字,通过设置步长来指定不连续
						# v = range(0, 100, 5)
						#
						# for item in v:
						#     print(item)

					##### 练习题:根据用户输入的值,输出每一个字符以及当前字符所在的索引位置 #####
						# test = input(">>>")
						# for item in test:
						#     print(item)

						# 将文字 对应的索引打印出来:
						# test = input(">>>")
						# print(test)   # test = qwe   test[0]   test[1]
						# l = len(test) # l = 3
						# print(l)
						#
						# r = range(0,l) # 0,3
						# for item in r:
						#     print(item, test[item]) # 0 q,1 w,2 e

						# test = input(">>>")
						# for item in range(0, len(test)):
						#     print(item, test[item])




					###################### 1个深灰魔法 ######################
					# 字符串一旦创建,不可修改
					# 一旦修改或者拼接,都会造成重新生成字符串

					# name = "zhengjianwen"
					# age = "18"
					#
					# info = name + age
					# print(info)

			
		列表   list
			...
		元祖   tuple
			...
		字典   dict
			...
		
		布尔值 bool
			...
	
		----> 列表,元祖,字典,布尔值 详细操作见课上代码
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
		
	
	
	
	
#!/usr/bin/env python
# -*- coding:utf-8 -*-

# v = "李杰"
# for item in v:
#     print(item)
####################################################################################################
# str
# name = "alex"

# list  # 类,列表
# li = [1, 12, 9, "age", ["石振文", ["19", 10], "庞麦郎"], "alex", True]  # 通过list类创建的对象,li
# list 类
# list类的一个对象


#######################################灰魔法: list类中提供的方法 #######################################

# li = [11, 22, 33, 22, 44]
# 参数
# 1. 原来值最后追加
# 对象.方法(..)   # li对象调用append方法
# li.append(5)
# li.append("alex")
# li.append([1234,2323])
# print(li)
# 2 清空列表
# li.clear()
# print(li)

# 3 拷贝,浅拷贝
# v = li.copy()
# print(v)
# 4. 计算元素出现的次数
# v = li.count(22)
# print(v)

# 5. 扩展原列表,参数:可迭代对象
# li = [11, 22, 33, 22, 44]
# li.append([9898,"不得了"])
# [11, 22, 33, 22, 44, [9898, '不得了']]

# li.extend([9898,"不得了"])
# for i in [9898,"不得了"]:
#     li.append(i)
# [11, 22, 33, 22, 44, 9898, '不得了']
#
# li.extend("不得了")
# print(li)

# 6. 根据值获取当前值索引位置(左边优先)
# li = [11, 22, 33, 22, 44]
# v= li.index(22)
# print(v)

# 7. 在指定索引位置插入元素
# li = [11, 22, 33, 22, 44]
# li.insert(0,99)
# print(li)

# 8、 删除某个值(1.指定索引;2. 默认最后一个),并获取删除的值
# li = [11, 22, 33, 22, 44]
# v = li.pop()
# print(li)
# print(v)

# li = [11, 22, 33, 22, 44]
# v = li.pop(1)
# print(li)
# print(v)
# 9. 删除列表中的指定值,左边优先
# li = [11, 22, 33, 22, 44]
# li.remove(22)
# print(li)
# PS: pop remove del li[0]    del li[7:9]   clear

# 10 将当前列表进行翻转
# li = [11, 22, 33, 22, 44]
# li.reverse()
# print(li)

# 11 列表的排序
# li = [11,44, 22, 33, 22]
# li.sort()
# li.sort(reverse=True)
# print(li)
### 欠
# cmp
# key
# sorted

####################################### 深灰魔法 #######################################
# 1. 列表格式
# 2. 列表中可以嵌套任何类型
# 中括号括起来
# ,分割每个元素
# 列表中的元素可以是 数字,字符串,列表,布尔值..所有的都能放进去
# “集合”,内部放置任何东西
"""
# 3.
# 索引取值
print(li[3])
# 4 切片,切片结果也是列表
print(li[3:-1])

# 5 for循环
# while循环
for item in li:
    print(item)
"""
# 列表元素,可以被修改

# li = [1, 12, 9, "age", ["石振文", ["19", 10], "庞麦郎"], "alex", True]

############## 6 索引
# 修改
# li[1] = 120
# print(li)
# li[1] = [11,22,33,44]
# print(li)

# 删除,第一种方式
# del li[1]
# print(li)
############## 7 切片
# 修改
# li[1:3] = [120,90]
# print(li)
# 删除
# del li[2:6]
# print(li)

# 8 in 操作
# li = [1, 12, 9, "age", ["石振文", ["19", 10], "庞麦郎"], "alex", True]
# v1 = "石振文" in li
# print(v1)
# v2 = "age" in li
# print(v2)
###### 列表中的元素,

# 9 操作
# li = [1, 12, 9, "age", ["石振文", ["19", 10], "庞麦郎"], "alex", True]
# li[4][1][0]
# [1]

# li = [1, 12, 9, "age", ["石振文", ["19", 10], "庞麦郎"], "alex", True]

# s = "pouaskdfauspdfiajsdkfj"
# s = 123
# a = "123"
# int(a)
# a = 123
# str(a)
# 10 转换
# 字符串转换列表   li =  list("asdfasdfasdf"), 内部使用for循环
# s = "pouaskdfauspdfiajsdkfj"
# new_li = list(s)
# print(new_li)

# 列表转换成字符串,
# 需要自己写for循环一个一个处理: 既有数字又有字符串
# li = [11,22,33,"123","alex"]
# # r = str(li) # '[11,22,33,"123","alex"]'
# # print(r)
# s = ""
# for i in li:
#     s = s + str(i)
# print(s)
# 直接使用字符串join方法:列表中的元素只有字符串
# li = ["123","alex"]
# v = "".join(li)
# print(v)

### 补充:字符串创建后,不可修改
# v = "alex"
# v = v.replace('l','el')
# print(v)

# li = [11,22,33,44]
# li[0]
# li[0] = 999

# s = "alex"
# li[0]
# s[0] = "E"

# li = [11,22,33,44]
# print(li)
# print(li)
# print(li)
# print(li)
# print(li)
# print(li)
# print(li)
# print(li)
# 列表,有序;元素可以被修改

# 列表
# list
# li = [111,22,33,44]


####################################################################################################

# 元组,元素不可被修改,不能被增加或者删除
# tuple
# tu = (11,22,33,44)
# tu.count(22),获取指定元素在元组中出现的次数
# tu.index(22)

####################################### 深灰魔法 #######################################
# 1. 书写格式
# tu = (111,"alex",(11,22),[(33,44)],True,33,44,)
# 一般写元组的时候,推荐在最后加入 ,
# 元素不可被修改,不能被增加或者删除
# 2. 索引
# v = tu[0]
# print(v)

# 3. 切片
# v = tu[0:2]
# print(v)

# 4. 可以被for循环,可迭代对象
# for item in tu:
#     print(item)

# 5. 转换
# s = "asdfasdf0"
# li = ["asdf","asdfasdf"]
# tu = ("asdf","asdf")
#
# v = tuple(s)
# print(v)

# v = tuple(li)
# print(v)

# v = list(tu)
# print(v)

# v = "_".join(tu)
# print(v)

# li = ["asdf","asdfasdf"]
# li.extend((11,22,33,))
# print(li)

# 6.元组的一级元素不可修改/删除/增加
# tu = (111,"alex",(11,22),[(33,44)],True,33,44,)
# # 元组,有序。
# # v = tu[3][0][0]
# # print(v)
# # v=tu[3]
# # print(v)
# tu[3][0] = 567
# print(tu)

####################################################################################################
# 字典
# dict
# dict
# dic = {
#     "k1": 'v1',
#     "k2": 'v2'
# }
# 1 根据序列,创建字典,并指定统一的值
# v = dict.fromkeys(["k1",123,"999"],123)
# print(v)

# 2 根据Key获取值,key不存在时,可以指定默认值(None)
# v = dic['k11111']
# print(v)
# v = dic.get('k1',111111)
# print(v)

# 3 删除并获取值
# dic = {
#     "k1": 'v1',
#     "k2": 'v2'
# }
# v = dic.pop('k1',90)
# print(dic,v)
# k,v = dic.popitem()
# print(dic,k,v)

# 4 设置值,
# 已存在,不设置,获取当前key对应的值
# 不存在,设置,获取当前key对应的值
# dic = {
#     "k1": 'v1',
#     "k2": 'v2'
# }
# v = dic.setdefault('k1111','123')
# print(dic,v)

# 5 更新
# dic = {
#     "k1": 'v1',
#     "k2": 'v2'
# }
# dic.update({'k1': '111111','k3': 123})
# print(dic)
# dic.update(k1=123,k3=345,k5="asdf")
# print(dic)

# 6 keys()  7 values()   8 items()   get   update
##########



# 1、基本机构
# info = {
#     "k1": "v1", # 键值对
#     "k2": "v2"
# }
#### 2 字典的value可以是任何值
# info = {
#     "k1": 18,
#     "k2": True,
#     "k3": [
#         11,
#         [],
#         (),
#         22,
#         33,
#         {
#             'kk1': 'vv1',
#             'kk2': 'vv2',
#             'kk3': (11,22),
#         }
#     ],
#     "k4": (11,22,33,44)
# }
# print(info)

####  3 布尔值(1,0)、列表、字典不能作为字典的key
# info ={
#     1: 'asdf',
#     "k1": 'asdf',
#     True: "123",
#     # [11,22]: 123
#     (11,22): 123,
#     # {'k1':'v1'}: 123
#
# }
# print(info)

# 4 字典无序

# info = {
#     "k1": 18,
#     "k2": True,
#     "k3": [
#         11,
#         [],
#         (),
#         22,
#         33,
#         {
#             'kk1': 'vv1',
#             'kk2': 'vv2',
#             'kk3': (11,22),
#         }
#     ],
#     "k4": (11,22,33,44)
# }
# print(info)

# 5、索引方式找到指定元素
# info = {
#     "k1": 18,
#     2: True,
#     "k3": [
#         11,
#         [],
#         (),
#         22,
#         33,
#         {
#             'kk1': 'vv1',
#             'kk2': 'vv2',
#             'kk3': (11,22),
#         }
#     ],
#     "k4": (11,22,33,44)
# }
# # v = info['k1']
# # print(v)
# # v = info[2]
# # print(v)
# v = info['k3'][5]['kk3'][0]
# print(v)

# 6 字典支持 del 删除
# info = {
#     "k1": 18,
#     2: True,
#     "k3": [
#         11,
#         [],
#         (),
#         22,
#         33,
#         {
#             'kk1': 'vv1',
#             'kk2': 'vv2',
#             'kk3': (11,22),
#         }
#     ],
#     "k4": (11,22,33,44)
# }
# del info['k1']
#
# del info['k3'][5]['kk1']
# print(info)

# 7 for循环
# dict
# info = {
#     "k1": 18,
#     2: True,
#     "k3": [
#         11,
#         [],
#         (),
#         22,
#         33,
#         {
#             'kk1': 'vv1',
#             'kk2': 'vv2',
#             'kk3': (11,22),
#         }
#     ],
#     "k4": (11,22,33,44)
# }
# for item in info:
#     print(item)
#
# for item in info.keys():
#     print(item)

# for item in info.values():
#     print(item)

# for item in info.keys():
#     print(item,info[item])

# for k,v in info.items():
#     print(k,v)

# True 1  False 0
# info ={
#     "k1": 'asdf',
#     True: "123",
#     # [11,22]: 123
#     (11,22): 123,
#     # {'k1':' v1'}: 123
#
# }
# print(info)

####################### 整理 #################

# 一、数字
# int(..)
# 二、字符串
# replace/find/join/strip/startswith/split/upper/lower/format
# tempalte = "i am {name}, age : {age}"
# # v = tempalte.format(name='alex',age=19)
# v = tempalte.format(**{"name": 'alex','age': 19})
# print(v)
# 三、列表
# append、extend、insert
# 索引、切片、循环
# 四、元组
# 忽略
# 索引、切片、循环         以及元素不能被修改
# 五、字典
# get/update/keys/values/items
# for,索引

# dic = {
#     "k1": 'v1'
# }

# v = "k1" in dic
# print(v)

# v = "v1" in dic.values()
# print(v)
# 六、布尔值
# 0 1
# bool(...)
# None ""  () []  {} 0 ==> False



























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转载自blog.csdn.net/ljwy1234/article/details/82982413