62个Python常用函数,从基础到进阶(二)
32.isinstance()：检查对象是否为指定类型的实例number = 42 print(isinstance(number, int)) # 输出: True33.callable()：检查对象是否可调用（函数、方法等）def say_hello(): print("Hello!") print(callable(say_hello)) # 输出: Trueclass Person: name = "Alice" person = Person() name = getattr(person, "name") print(name) # 输出: Aliceclass Person: name = "" person = Person() setattr(person, "name", "Alice") print(person.name) # 输出: Aliceclass Person: name = "Alice" person = Person() delattr(person, "name") print(hasattr(person, "name")) # 输出: Falsefile = open("example.txt", "r") content = file.read() print(content) file.close()file = open("example.txt", "r") content = file.read() file.close()file = open("example.txt", "r") content = file.read() print(content) file.close()file = open("example.txt", "w") file.write("Hello, World!") file.close()numbers = [1, 2, 3] numbers.append(4) print(numbers) # 输出: [1, 2, 3, 4]42.extend()：将可迭代对象中的元素添加到列表末尾numbers = [1, 2, 3] more_numbers = [4, 5, 6] numbers.extend(more_numbers) print(numbers) # 输出: [1, 2, 3, 4, 5, 6]numbers = [1, 2, 3] numbers.insert(1, 4) print(numbers) # 输出: [1, 4, 2, 3]44.remove()：移除列表中第一个匹配的元素numbers = [1, 2, 3, 2, 4] numbers.remove(2) print(numbers) # 输出: [1, 3, 2, 4]numbers = [1, 2, 3] popped = numbers.pop(1) print(popped) # 输出: 2 print(numbers) # 输出: [1, 3]numbers = [1, 2, 3, 2, 4] index = numbers.index(2) print(index) # 输出: 1numbers = [1, 2, 3, 2, 4] count = numbers.count(2) print(count) # 输出: 2numbers = [5, 2, 4, 1, 3] numbers.sort() print(numbers) # 输出: [1, 2, 3, 4, 5]numbers = [1, 2, 3, 4, 5] numbers.reverse() print(numbers) # 输出: [5, 4, 3, 2, 1]50.random.random()：生成 0 到 1 之间的随机浮点数import random print(random.random()) # 输出: 0.2203627（示例值）51.time.sleep()：让程序暂停指定时长（单位：秒）import time time.sleep(5) print('hello') # 延迟5秒后输出52.os.listdir()：显示指定目录下的文件和子目录列表import os path = r'D:/images' dirs = os.listdir(path) for file in dirs: print(file) # 输出目录下所有文件53.chr()：返回指定 Unicode 代码对应的字符char = chr(65) print(char) # 输出: 'A'54.ord()：返回字符对应的 Unicode 代码code = ord('A') print(code) # 输出: 65binary = bin(10) print(binary) # 输出: '0b1010'hexadecimal = hex(16) print(hexadecimal) # 输出: '0x10'octal = oct(8) print(octal) # 输出: '0o10'58.bytearray()：创建一个可变的字节数组对象my_array = bytearray([0, 1, 2, 3]) print(my_array) # 输出: bytearray(b'\x00\x01\x02\x03')59.bytes()：创建一个不可变的字节数组对象my_bytes = bytes([0, 1, 2, 3]) print(my_bytes) # 输出: b'\x00\x01\x02\x03'60.frozenset()：创建一个不可变的集合对象my_set = frozenset([1, 2, 3, 2]) print(my_set) # 输出: frozenset({1, 2, 3})61.ascii()：返回对象的可打印字符串表示，非 ASCII 字符会转义text = "Hello, 你好" ascii_text = ascii(text) print(ascii_text) # 输出: 'Hello, \u4f60\u597d'62.exec()：执行动态生成的 Python 代码code = ''' for i in range(5): print(i) ''' exec(code) # 输出: 0 1 2 3 463.format()：根据指定格式进行字符串格式化name = "Alice" age = 25 formatted = "Name: {}, Age: {}".format(name, age) print(formatted) # 输出: "Name: Alice, Age: 25"
