被搞得头疼,已经放弃试图理解它的运行机制了..

请预测以下脚本的运行结果:

========================
'文件a'

exec('a = 1')
print(a)

========================
'文件b'

def f():
    exec('a = 1')
    print(a)

f()

========================
'文件c'

a = 1
exec('a = 2')
print(a)

========================
'文件d'

def f():
    a = 1
    exec('a = 2')
    print(a)

========================
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修改:annals FROM 61.149.74.61
FROM 61.149.74.61