diff --git a/2022.03.16_frequently_used_python_package/python_example.py b/2022.03.16_frequently_used_python_package/python_example.py index 06df20c..a8f8023 100644 --- a/2022.03.16_frequently_used_python_package/python_example.py +++ b/2022.03.16_frequently_used_python_package/python_example.py @@ -1,9 +1,60 @@ -a = [1, 2] # 数组 +a = [1, 2] # list列表 print(a) -print(len(a)) # 数组长度 -a.append(3) # 增加元素 +print(type(a)) # 对象类型 +print(id(a)) # 对象唯一标识符 +print(len(a)) # 列表长度 +a.append(3) # list列表增加元素 print(a) -b = range(5) # 数列(从0开始) -print(b) -for i0 in b: - print(i0) \ No newline at end of file +print(sum(a)) # 求和 +print(max(a)) # 最大值 +print(min(a)) # 最小值 +print(abs(-3.14)) # 绝对值 +b1 = [2, -1, 3] +b2 = sorted(b1) # 排序,不改变原数列 +print(b1) +print(b2) +b3 = list(reversed(b1)) # 反向并转为list列表 +print(b1) +print(b3) +c = range(5) # 数列,从0开始 +print(c) +for i0 in c: + print(i0) +d1 = [1, 2, 3, 3, 2, 1, 1] +d2 = set(d1) # 转成集合,去除重复元素 +print(d1) +print(d2) +print(list(d2)) + +print() +dict_data = {"name": "张三", "age": 30, "city": "北京"} # dict字典 +print(dict_data) +print(type(dict_data)) +print(dict_data.items()) +for key, value in dict_data.items(): + print(f'打印字典内容 {key} {value}') + +print() # 打印空一行 +print(all([True, True, False])) # 所有元素为真,结果为真 +print(all([1, 2, True])) +print(any([True, True, False])) # 有一个是真,结果为真 +print(any([0, None, ""])) + +print() +e = 'abc' +print(e) +print(hash(e)) # 哈希值(如果是多次运行,对于相同的对象,返回的哈希值是不同的) +print(hash(e)) # 哈希值(同一个运行中多次调用 hash(),对于相同的对象,返回的哈希值是相同的) + +print() +for i0 in range(3): + exec(f''' +a{i0} = {i0} +print(a{i0}) +''') # 执行动态创建的代码 +f = eval('1+2') # 执行表达式并返回值 +print(f) + +f = open('a.txt', 'w') # 打开文件 +f.write('test') # 写入文件 +f.close() # 关闭文件 \ No newline at end of file