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在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807
跟C语言不同，Python的长整数没有指定位宽，即：Python没有限制长整数数值的大小，但实际上由于机器内存有限，我们使用的长整数数值不可能无限大。注意，自从Python2.2起，如果整数发生溢出，Python会自动将整数数据转换为长整数，所以如今在长整数数据后面不加字母L也不会导致严重后果了。
浮点数用来处理实数，即带有小数的数字。类似于C语言中的double类型，占8个字节（64位），其中52位表示底，11位表示指数，剩下的一位表示符号。
复数由实数部分和虚数部分组成，一般形式为x＋yj，其中的x是复数的实数部分，y是复数的虚数部分，这里的x和y都是实数。注：Python中存在小数字池：-5 ～ 257
1 或 0True 或 False
"hello world"
python中的字符串在C语言中体现为是一个字符数组，每次创建字符串时候需要在内存中开辟一块连续的空，并且一旦需要修改字符串的话，就需要再次开辟空间，万恶的+号每出现一次就会在内从中重新开辟一块空间。
name = "zhangcong"print "i am %s " % name# 输出i am zhangcong
strip() # 去掉字符串首尾空格、换行符、tab
value = " my name is zhangcong "print(value.strip()) # 会将首尾的空格去掉# 输出my name is zhangcong
split() # 通过指定分隔符对字符串进行切片，得到一个列表
names = "zhangsan, lisi, wangwu"name2 = names.split(",")print(name2)# 输出[‘zhangsan‘, ‘ lisi‘, ‘ wangwu‘]
center() # 返回一个原字符串居中,并使用空格填充至长度 width 的新字符串。默认填充字符为空格。
例1：value = "my name is zhangcong"print(value.center(50))# 输出my name is zhangcong例2：# 使用*填充空格value = "my name is zhangcong"print(value.center(50, ‘*‘))# 输出***************my name is zhangcong***************
find() # 字符串查找
例1：# 在字符串value中查找字符串"zhangcong"是否存在，如果存在返回其下标值value = "my name is zhangcong"print(value.find("zhang"))# 输出11-例2：# 指定开始的位置查找value = "my name is zhangcong, my name is zhangcong"print(value.find("zhang", 12))# 输出33
capitalize() # 首字母大写，没什么卵用
value = "my name is zhangcong, my name is zhangcong"print(value.capitalize())# 输出My name is zhangcong, my name is zhangcong
upper() # 将字符串里面的所有字母都改为大写
value = "43 fd"print(value.upper())# 输出43 FD
format() 格式化字符串
value = "my name is {}"print(value.format("zhangcong"))# 输出my name is zhangcong
isdigit() # 判断字符串是否是数字类型 返回True 或 False
例1：value = "my name is {}"print(value.isdigit())# 输出False-例2：num_str = "1000"print(num_str.isdigit())# 输出True
isalnum() # 判断字符是否只含有字母和数字组成 返回True 或 False
例1：value = "43fd"print(value.isalnum())# 输出True-例2：# value中包含一个空格value = "43 fd"print(value.isalnum())# 输出False
endswith() # 匹配字符串的结束位置，返回True 或 False
value = "43 fd"print(value.endswith("fd"))# 输出True-print(value.endswith("c"))# 输出False
startswith() # 匹配字符串的开始位置，返回True 或 False
value = "43 fd"print(value.startswith("4"))# 输出True-print(value.startswith("fda"))# 输出False
# 创建列表name_list = ["zhangsan", "lisi", "wangwu"]或name_list = list(["zhangsan", "lisi", "wangwu"])# 通过列表的下标来取对应的值print(name_list[1])# 输出lisi
修改列表中的值
# 将name_list中的 "lisi" 修改为 "liwu"name_list = ["zhangsan", "lisi", "wangwu"]name_list[1] = "liwu" # 指定下标修改列表的值print(name_list)# 输出[‘zhangsan‘, ‘liwu‘, ‘wangwu‘]
切片
# 输出name_list中的第一个值和第二个值name_list = ["zhangsan", "lisi", "wangwu", 1, 2, 3, 4, 5]print(name_list[1:3]) # 顾头不顾尾# 输出[‘lisi‘, ‘wangwu‘]
步长
# 首先创建一个从0到100的列表，不包含100num_list = list(range(100))print(num_list[::2])# 输出[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98]# 注：通过步长可以取奇偶数
insert() # 指定坐标插入值
# 在列表name_list的值"lisi"前面插入一个值"xiaogou"name_list = ["zhangsan", "lisi", "wangwu"]name_list.insert(1, "xiaogou")print(name_list)# 输出[‘zhangsan‘, ‘xiaogou‘, ‘lisi‘, ‘wangwu‘]
append() # 在列表的末尾追加一个值
name_list = ["zhangsan", "lisi", "wangwu"]name_list.append("xiaogou")print(name_list)# 输出[‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘xiaogou‘]
remove() # 删除列表中的指定值
name_list = ["zhangsan", "lisi", "wangwu"]name_list.remove("lisi")print(name_list)# 输出[‘zhangsan‘, ‘wangwu‘]# 如果删除的值不在列表中，则会报错name_list = ["zhangsan", "lisi", "wangwu"]name_list.remove("lisfdi")print(name_list)# 输出报错信息ValueError: list.remove(x): x not in list
count() # 查找在列表中出现的次数
name_list = ["zhangsan", "lisi", "wangwu", "lisi", 1, 2, 3, 4, 5]print(name_list.count("lisi")) # 查找"lisi"在列表中出现的次数# 输出2
index() # 查找在列表中的下标
name_list = ["zhangsan", "lisi", "wangwu", "lisi", 1, 2, 3, 4, 5]print(name_list.index("lisi"))# 输出1-# 如果查找的值在列表中不存在，则会报错name_list = ["zhangsan", "lisi", "wangwu", "lisi", 1, 2, 3, 4, 5]print(name_list.index("lisi2"))# 输出报错信息ValueError: ‘lisi2‘ is not in list
extend() # 在原先列表的基础之上扩展一个新的列表
name_list = ["zhangsan", "lisi", "wangwu", "lisi"]name_list2 = [1, 2, 3, 4, 5]name_list.extend(name_list2)print(name_list)# 输出[‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, 1, 2, 3, 4, 5]
reverse() # 将列表的值进行反转
name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, 1, 2, 3, 4, 5]name_list.reverse()print(name_list)# 输出[5, 4, 3, 2, 1, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘zhangsan‘]
sort() # 排序
# 在python3中，列表中的值同时存在字符串和数字时排序是会报错的，在python2中是没有问题的，python2中是按照ascll编码顺序进行排序的name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, 1, 2, 3, 4, 5]name_list.sort()# 输错报错信息TypeError: unorderable types: int() < str()-# 对字母进行排序name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘]name_list.sort()print(name_list)# 输出[‘lisi‘, ‘lisi‘, ‘wangwu‘, ‘zhangsan‘]-# 对数字进行排序num_list = [3, 4, 1, 100, 3, 5, 6]num_list.sort()print(num_list)# 输出[1, 3, 3, 4, 5, 6, 100]
pop() # 默认删除列表最后的一个值，并返回删掉的那个值
name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]pop_name = name_list.pop()print(name_list)print(pop_name)# 输出[‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘]44-# 指定下标删除列表元素name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]pop_name = name_list.pop(2)print(name_list)print(pop_name)# 输出[‘zhangsan‘, ‘lisi‘, ‘lisi‘, ‘44‘]wangwu
copy() # 浅拷贝 可以通过id()查看内存地址看区别
name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]name_list2 = name_list.copy()print("name_list: %s" % name_list)print("name_list2: %s" % name_list2)# 将name_list中的‘zhangsan‘改为‘liusan‘name_list[0] = ‘liusan‘print("修改完之后")print("name_list: %s" % name_list)print("name_list2: %s" % name_list2)# 输出name_list: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]name_list2: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]修改完之后name_list: [‘liusan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]name_list2: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘]-# 在name_list中嵌套一个列表，然后拷贝一份，然后在修改嵌套列表中的值name_list = [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘, [3, 4, 1, 100, 3, 5, 6]]name_list2 = name_list.copy()print("name_list: %s" % name_list)print("name_list2: %s" % name_list2)# 将name_list中的‘zhangsan‘改为‘liusan‘name_list[-1][0] = ‘liusan‘print("修改完之后")print("name_list: %s" % name_list)print("name_list2: %s" % name_list2)# 输出# 可以看到name_list中嵌套列表中的值被修改，name_list2也随着变化，浅拷贝只能操作第一层name_list: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘, [3, 4, 1, 100, 3, 5, 6]]name_list2: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘, [3, 4, 1, 100, 3, 5, 6]]修改完之后name_list: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘, [‘liusan‘, 4, 1, 100, 3, 5, 6]]name_list2: [‘zhangsan‘, ‘lisi‘, ‘wangwu‘, ‘lisi‘, ‘44‘, [‘liusan‘, 4, 1, 100, 3, 5, 6]]# 浅拷贝与=之间的区别，等于号相当于软连接，浅拷贝类似于上面
# 字典是以key和value的形式出现的id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}# 输出字典中key为id_db[22323232]的值print(id_db[22323232])# 修改字典中key为22323232的key "name"的值id_db[22323232]["name"] = "Wangwu"print(id_db)# 输出{‘age‘: 22, ‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘}{22323232: {‘age‘: 22, ‘addr‘: ‘ShanDong‘, ‘name‘: ‘Wangwu‘}, 43267432: {‘age‘: 24, ‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘}}
字典常用功能
pop() # 对指定key进行删除,并返回其value
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}print(id_db)v = id_db.pop(43267432)print(v)print(id_db)# 输出# 字典id_db的值{22323232: {‘age‘: 22, ‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘}, 43267432: {‘age‘: 24, ‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘}}# 通过pop()删除的值{‘age‘: 24, ‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘}# 通过pop()删除之后的值{22323232: {‘age‘: 22, ‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘}}
get() # 通过key获取值
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}print(id_db.get(43267432))# 输出{‘age‘: 24, ‘name‘: ‘DaShanPao‘, ‘addr‘: ‘DongBei‘}
update() # 对已经存在的key进行更新，没有的key进行添加
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}dic2 = {22323232: {"name": "DaShaXXXXXXX","age": 22,"addr": "ShanDong"},"name": "acong",43267432: "xxxxxx"}print(id_db)id_db.update(dic2)print(id_db)# 输出{22323232: {‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘, ‘age‘: 22}, 43267432: {‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘, ‘age‘: 24}}{22323232: {‘addr‘: ‘ShanDong‘, ‘name‘: ‘DaShaXXXXXXX‘, ‘age‘: 22}, 43267432: ‘xxxxxx‘, ‘name‘: ‘acong‘}
items() # 将字典的key和value放到一个元组中，多组key和value放入到到一个列表中，转成这种格式： [(key, value), (key, value)]
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}print(id_db.items())# 输出dict_items([(22323232, {‘age‘: 22, ‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘}), (43267432, {‘age‘: 24, ‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘})])
keys() # 输出字典所有的key
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}print(id_db.keys())# 输出dict_keys([22323232, 43267432])
values() # 输出字典所有的value
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}print(id_db.values())# 输出dict_values([{‘name‘: ‘ShanPao‘, ‘addr‘: ‘ShanDong‘, ‘age‘: 22}, {‘name‘: ‘DaShanPao‘, ‘addr‘: ‘DongBei‘, ‘age‘: 24}])
has_key() # 查找key是否在字典中存在，只能在python2里面使用，python3使用in判断
setdefault() # 指定一个key，如果字典存在这个key，则返回该key的值，否则创建这个key，如果setdefault()括号内为空，则创建的key的value 为None，否则为该括号内填写的值
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}value = id_db.setdefault(43267432)print(value)value2 = id_db.setdefault(432674323232)print(value2)print(id_db)# 输出{‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘, ‘age‘: 24}None{22323232: {‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘, ‘age‘: 22}, 43267432: {‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘, ‘age‘: 24}, 432674323232: None}
popitem() # 随机删除字典中的指定的key
id_db = {22323232: {"name": "ShanPao","age": 22,"addr": "ShanDong"},43267432:{"name": "DaShanPao","age": 24,"addr": "DongBei"}}print(id_db.popitem())print(id_db)# 输出(22323232, {‘age‘: 22, ‘addr‘: ‘ShanDong‘, ‘name‘: ‘ShanPao‘}){43267432: {‘age‘: 24, ‘addr‘: ‘DongBei‘, ‘name‘: ‘DaShanPao‘}}
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原文地址：http://www.cnblogs.com/CongZhang/p/5533108.html
