Python各数据类型详细功能介绍

一、str 字符串
字符串属于不可变类型,对字符串对象的进行的任何功能性操都不会改变字符串本身。

a.字符串常用功能：
1.lower 将所有大写变小写（功能不如casefold，仅支持英文）
name = 'SMITH'
v = name.lower()
print(v)

2. upper 将所有小写变大写
name = 'smith'
v = name.upper()
print(v)

3. startswith 检查是否以指定值开头
name = 'smith'
v = name.startswith('sm')
print(v)

4.endswith 检查是否以指定值结尾
name = 'smith'
v = name.endswith('h')
print(v)

5.find 找到指定子序列索引位置，不存在返回-1
name = 'smith'
v = name.find('i')
print(v)

6.strip 删除字符串两边的空格；lstrip 删除左边的空格；rstrip 删除右边的空格
name = ' al ex '
v = name.strip()
print(v)

7.split 对字符串进行分割
content = "nixhaoxma"
v = content.split('x')
print(v)

8. replace 对字符串进行替换
content = "NieoSBSmithSBZion"
v = content.replace('SB','->')
print(v)

9. join 元素拼接（元素字符串）
name = 'smith'
v = "/".join(name)
print(v)

b. 字符串其他功能

1. capitalize 字符串首字母大写
name = 'smith'
v = name.capitalize()
print(v)

2. casefold 将所有大写变小写（并且还支持其他语言，如：德语）
name = 'SMITH'
v = name.casefold()
print(v)

3.center 文本居中
name = 'Smith'
v = name.center(20,'*')
print(v)

4.ljust\rjust 左右填充
name = 'Smith'
v1 = name.ljust(20,'*')
v2 = name.rjust(20,'*')
print(v1)
print(v2)

5. count 查看传入字符在字符串中出现的次数
参数1：要查找的值（子序列）
参数2：起始位置（索引）
参数3：结束位置（索引）
name = 'jlksjlkkjalkjflkjdlkglkjlkgdsajlk'
v = name.count('lk')
print(v)
v1 = name.count('k',8,-1)
print(v1)

6. expandtabs 找到制表符\t,进行替换（指定的长度包含值）
name = "sm\tith\teric"
v = name.expandtabs(20)
print(v)

7. index 找到指定子序列索引位置，不存在报错
name = 'smith'
v = name.index('t')
print(v)
v1 = name.index('x')
print(v1)

8. format\format_map 字符串格式化
tp1 = "我是:{0};年龄:{1};性别:{2}"
v = tp1.format("东方不败",18,"不知道")
print(v)

tp1 = "我是:{name};年龄:{age};性别:{gender}"
v = tp1.format(name='东方不败',age=18,gender='随意')
print(v)

tp1 = "我是:{name};年龄:{age};性别:{gender}"
v = tp1.format_map({'name':'东方不败','age':18,'gender':'女'})
print(v)

9. isalpnum\isalpha 判断字符串是否是字母、汉字、数字
name = 'alex123好'
v = name.isalnum()
print(v)
name = 'alex好'
v = name.isalpha()
print(v)

10. isdecimal\isdigit\isnumeric 判断字符串是否是数字
num = '1234二②⑩'
v1 = num.isdecimal() #'1234'
v2 = num.isdigit() #'1234②⑩'
v3 = num.isnumeric() #'1234二②⑩'print(v1,v2,v3) 11. isidentifier 判断字符串是否是表示符（能否作为变量名）n = '_name8'v = n.isidentifier()print(v) 12. printable 判断字符串是否包含隐藏的字符（\t,\n 等）name = "今天真热啊,\t好几天没下雨了"v = name.isprintable()print(v) 13. maketrans 创建字符映射的转换表（翻译）n = str.maketrans('abcd','1234')name = "abcdefghijklmnabcilniabcd"v = name.translate(n)print(v) 14. partition\rpartition 对字符串进行分割，保留分割的元素content = "张三PQ李四PQ王五"v = content.partition('PQ')print(v)v1 = content.rpartition('PQ')print(v1) 15. swapspace 对字符串进行大小写转换name = 'Smith'v = name.swapcase()print(v) 16. zfill 对字符串填充0name = 'nieo'v = name.zfill(20)print(v) 二、int 数字整数属于不可变类型,对整数对象的进行的任何功能性操都不会改变整数本身。1. bit_length 当前整数的二进制表示，最少位数age = 30print(age.bit_length()) 2.to_bytes 获取当前数据的字节表示age = 30v = age.to_bytes(10,byteorder='big')print(v)v1 = age.to_bytes(5,byteorder='little')print(v1) 三、list 列表:列表属于可变类型，对列表对象进行的功能性操作，会改变列表本身。 1. append 追加元素user_list = ['smith','zion','alex']user_list.append('nike')print(user_list) 2. remove 删除元素user_list = ['smith','zion','alex']user_list.remove('zion')print(user_list) 3. pop 删除并获取元素（索引方式）user_list = ['smith','zion','alex']v = user_list.pop(2)print(user_list)print(v) 4. copy 拷贝（浅拷贝）user_list = ['smith','zion','alex']v = user_list.copy()print(v)print(user_list) 5. count 计数user_list = ['smith','zion','alex','zion']v = user_list.count('zion')print(v) 6. extend 扩展原列表user_list = ['smith','zion','alex']user_list.extend(['nieo','nike','joe'])print(user_list) 7. reverse 反转列表user_list = ['smith', 'zion', 'alex', 'nieo', 'nike', 'joe']user_list.reverse()print(user_list) 8. sort 排序(正向)num = [20,30,40,21,23,33]num.sort()print(num)name = ['smith', 'zion', 'alex', 'nieo', 'nike', 'joe']name.sort()print(name) 9. clear 清空user_list = ['smith', 'zion', 'alex', 'nieo', 'nike', 'joe']user_list.clear()print(user_list) 列表的额外功能：1. 切片user_list = ['smith', 'zion', 'alex', 'nieo', 'nike', 'joe']v = user_list[2]print(v)v1 = user_list[2:5:2]print(v1)user_list1 = ['smith', 'zion', 'alex', ['nieo','jack','jones'], 'nike', 'joe']v2 = user_list1[3][1:]print(v2) 2. 长度(计算列表中的元素个数)user_list1 = ['smith', 'zion', 'alex', ['nieo','jack','jones'], 'nike', 'joe']v = len(user_list1)print(v) 3. del 删除user_list1 = ['smith', 'zion', 'alex', ['nieo','jack','jones'], 'nike', 'joe']del user_list1[3][0:2] # 0 <= x <2print(user_list1) 4. insert 插入元素user_list1 = ['smith', 'zion', 'alex', ['nieo','jack','jones'], 'nike', 'joe']user_list1.insert(3,'Tony')print(user_list1) 四、tuple 元组:元组可以看做是不可被修改的列表，属于不可变类型，对元组对象进行的功能性操作，不会改变元组本身。 1. count 获取元素个数user_tuple = ('smith', 'zion', 'alex', ['nieo','jack','alex'], 'nike', 'joe')v = user_tuple.count('alex')print(v) 2. index 获取元素的第一个索引位置user_tuple = ('smith', 'zion', 'alex', ['nieo','jack','alex'], 'nike', 'joe')v = user_tuple.index('alex')print(v) 元组的其他功能1. 切片user_tuple = ('smith', 'zion', 'alex', ['nieo', 'jack', 'alex'], 'nike', 'joe')v = user_tuple[3][1:]print(v) 注：在填写元组内容时，需要在元组最后加逗号。v = ('joe',)print(v) 五、dict 字典：字典属于可变类型，对字典对象进行的功能性操作，会改变字典本身。字典可以嵌套，字典的key必须是不可变类型。 1. clear 清空字典dic = {'k1':'v1','k2':'v2'}dic.clear()print(dic) 2. copy 浅拷贝dic = {'k1':'v1','k2':'v2'}v = dic.copy()print(v) 3.get 根据key获取指定value，不存在不报错dic = {'k1':'v1','k2':'v2'}v = dic.get('k111')print(v) 4.pop 删除并获取对应的value值dic = {'k1':'v1','k2':'v2'}v = dic.pop('k2')print(dic)print(v) 5. popitem 随机删除键值对，并获取到删除的键值dic = {'k1':'v1','k2':'v2','k3':'v3','k4':'v4'}v = dic.popitem()print(dic)print(v) 6. setdefault 增加键值，如果存在则不做操作dic = {'k1':'v1','k2':'v2','k3':'v3','k4':'v4'}dic.setdefault('k5','v5')print(dic)dic.setdefault('k1','ddfdg')print(dic) 7. update 批量增加或修改dic = {'k1':'v1','k2':'v2','k3':'v3','k4':'v4'}dic.update({'k1':111,'k7':777})print(dic) 8. fromkeys 拷贝字典的键dic = {'k1':'v1','k2':'v2','k3':'v3','k4':'v4'}d1 = dic.fromkeys(['k1','k2','k3'],123)d2 = dic.fromkeys(['k2','k3','k4'],['11','22','33'])print(dic)print(d1)print(d2) 六、set集合集合可以看做是不可重复的列表，属于可变类型，对集合对象进行的功能性操作，会改变集合本身。 1. difference s1中存在，s2中不存在s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s2 = {'smith', 'white', 'blues', 'jack', 'cat', 'joe'}v = s1.difference(s2)print(v) 2. symmteric_difference 返回s1和s2中不重复的值s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s2 = {'smith', 'white', 'blues', 'jack', 'cat', 'joe'}v = s1.symmetric_difference(s2)print(v) 3. intersection 返回s1和s2的交集s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s2 = {'smith', 'white', 'blues', 'jack', 'cat', 'joe'}v = s1.intersection(s2)print(v) 4. union 返回s1和s2的并集s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s2 = {'smith', 'white', 'blues', 'jack', 'cat', 'joe'}v = s1.union(s2)print(v) 5.移除操作s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s1.discard('alex')print(s1) 6.update 批量更新，但不新增已存在的值s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s1.update({'alex','jone','jobs'})print(s1) 7. discard 移除操作s1 = {'smith', 'zion', 'alex', 'nieo', 'nike', 'joe'}s1.discard('nike')print(s1) 七、部分函数的用法：a. range函数: 1.range函数在python 2中会直接生成所有的数字，在python 3中不会立即生成，只有在循环迭代时，才一个一个生成。python 2.7中的xrange和python 3 中的range功能相同。for i in range(10,0,-2): print(i) 2. range 循环显示列表中的元素user_list = ['smith','joe','jack']for i in range(0,len(user_list)): n = user_list[i] print(n) b. enumerate函数:enumerate 额外生成一列有序的数字user_list = ['smith','joe','jack']for i,ele in enumerate(user_list,1): print(i,ele)