Python开发【第二篇】：Python基本数据类型
运算符
一、数字运算
二、比较运算
三、赋值运算
四、逻辑运算
五、成员运算
基本数据类型
一、数字
int（整型）
在32位机器上，整数的位数为32位，取值范围为-231～231-1，即-2147483648～2147483647
在64位系统上，整数的位数为64位，取值范围为-263～263-1，即-9223372036854775808～9223372036854775807
- 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()二、字符串
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
字符串常用功能
- join
- split
- find
- strip
- upper
- lower
- replace
# 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)
# 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 =
# 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)# 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)
# 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)三、列表
列表格式
- 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
- 列表，有序；元素可以被修改
#########################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)####################################### 深灰魔法 #######################################
# 1.
# 索引取值
print(li[3])
# 2 切片，切片结果也是列表
print(li[3:-1])
# 3 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]
############## 4 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)
############## 5 切片
# 修改
# li[1:3] = [120,90]
# print(li)
# 删除
# del li[2:6]
# print(li)
# 6 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)
# 7 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)四、元组
元组，元素不可被修改，不能被增加或者删除
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)获取指定元素在元组的索引
# 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)五、字典
- 字典无序
- 字典的value可以是任何值
- 布尔值(1,0)、列表、字典不能作为字典的key**
# 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)- 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)- 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)- 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)- 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) 相关推荐
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