Python动态地声明变量赋值

Posted 2020-11-23 MilesMa

通过exec()、globals()和locals()

# 通过exec()
for i in range(1, 4):
    # 第一次循环 i=1 时,会执行字符串中的python语句 ex1 = "exec1",以此类推
    exec(f\'ex{i} = "exec{i}"\')

# 通过globals()和locals()
def test():
    # globals()
    for i in range(1, 4):
        # 第一次循环 i=1 时,执行 globals()[\'gb1\'] = \'global1\', globals()是一个dict
        globals()[f\'gb{i}\'] = f\'global{i}\'

    # locals()
    for i in range(1, 4):
        locals()[f\'lc{i}\'] = f\'local{i}\'

    # 尝试打印locals的变量
    try:
        print(lc1, lc2, lc3)    # 会报错
    except Exception as e:
        print(e)
        print(locals()[\'lc1\'], locals()[\'lc2\'], locals()[\'lc3\'])    # 通过键值对

if __name__ == \'__main__\':
    # 执行
    test()
    print(\'---------------------\')
    # 打印函数定义的全局变量
    print(gb1, gb2, gb3)
    print(\'---------------------\')
    # 打印通过exec()定义的变量
    print(ex1, ex2, ex3)

输出结果:

name \'lc1\' is not defined
local1 local2 local3
---------------------
global1 global2 global3
---------------------
exec1 exec2 exec3