python exec函数

exec函数:
作用:
把一个字符串当成’程序’来执行
示列
x = 100
y = 200
s = ‘’‘z=x+y
print(‘z=’, z)
print(“hello world!”)
‘’’
exec(s) # 执行 s这个字符串
print(z)

dict_local = {‘x’: 1}
exec(s, None, dict_local)
print(dict_local)

结果

z= 300

hello world!

300

z= 201

hello world!

{‘z’: 201, ‘x’: 1}