我遇到以下问题，我将共享四个不同的.py文件，以更好地说明自己。我正在从spyder（不是jupyter），python 3.4运行代码。 我有一个主脚本“ master001.py”，可以从中执行代码。看起来像这样：
import sys
before = [str(m) for m in sys.modules]
from importlib import reload
import time
#from child001 import calculation as calc
import child001
from child002 import calculation_two
from child003 import calculation_three
after = [str(m) for m in sys.modules]
print("########################")
print([m for m in after if not m in before])
print("########################\n")
stop = False
while stop == False:
print("\n\n\n\n\n\n\n")
reload_child_one = input("reload child 1 function? Enter Y or N\n")
reload_child_one = reload_child_one.lower()
if reload_child_one == "y":
print("Script will try to reload the calculation 1 / child 1 module.")
time.sleep(1)
reload(child001)
reload_child_two = input("reload child 2 function? Enter Y or N\n")
reload_child_two = reload_child_two.lower()
if reload_child_two == "y":
print("Script will try to reload the calculation 2 / child 2 module.")
time.sleep(1)
#reload(sys.modules[calculation_two.__module__])
#del calculation_two
#from child002 import calculation_two
#__import__("child002", fromlist='calculation_two')
calculation_two = reload(sys.modules["child002"]).calculation_two
print("\n####################################################")
a = input("Enter number that will be saved in variable 'a' or enter Q to quit prorgam\n")
if a.lower() == "q" :
stop = True
print("\nFunction complted. Script will quit.")
print("####################################################\n")
time.sleep(2)
else:
try:
a = int(a)
print("Master - Launching Child function 'calculation'")
b = child001.calculation(a)
print("\nMaster - Inside Master file. Result = b = {}".format(b))
print("####################################################\n")
print("Master - Launching Child 2 function 'calculation_two' on input variable")
c = calculation_two(a)
print("\nMaster - Inside Master file. Result = c = {}".format(c))
print("####################################################\n")
print("Master - Launching child 3")
calculation_three()
time.sleep(2)
except:
print("input value was not a valid number. Please, try again.\n")
print("####################################################\n")
time.sleep(2)
master001.py调用child001.py进行简单的计算：
print("wassupp from child 1 !!!")
def calculation(a):
print("\n----------------------------------------")
print("Child 1 - function 'calculation' started.")
print("Child 1 - Operation that will be executed is: input variable + 20")
result = a + 20
print("Child 1 - Returning result = {}".format(result))
print("----------------------------------------\n")
return result
然后，master001.py调用child002.py，在其中执行另一个简单的计算：
print("wassupp from child 2 !!!")
def calculation_two(a):
print("\n----------------------------------------")
print("Child 2 - function 'calculation_two' started.")
print("Child 2 - Operation that will be executed is: input variable + 200")
result = a + 200
print("Child 2 - Returning result = {}".format(result))
print("----------------------------------------\n")
return result
到目前为止，一切都很好。最后，我有child003.py。在此模块中，我执行的计算实际上是从child002.py
导入的from child002 import calculation_two
print("wassupp from child 3 !!!")
def calculation_three():
print("\n----------------------------------------")
print("Child 3 function - Calculation will use the one in child 2 applied to value '3'.!\n")
result = calculation_two(3)
print("Child 3 - result = {}".format(result))
print("----------------------------------------\n")
return
从运行master001.py可以看到，当我使用
重新加载Calculation_two时calculation_two = reload(sys.modules["child002"]).calculation_two
calculation_two的从child002.py运行，但是不会重新加载calculation_two调用的child003.py。
更具体地说，如果您运行master001.py并且在手动输入任何内容之前更改calculation_two的内容，那么当系统提示您
reload child 1 function? Enter Y or N
您输入N，当系统提示您输入
reload child 2 function? Enter Y or N
您输入Y，您将看到child003.py返回的值不反映新的更新代码。
我阅读了How do I unload (reload) a Python module?和How to reload python module imported using `from module import *`，它们非常有帮助，但是我找不到针对该特定问题的解决方案。
答案 0 :(得分：1)
您的问题在于如何从child002导入函数：
from child002 import calculation_two
这将创建对child003中功能对象的引用，并且该引用未替换。 Python名称就像绑在对象上的字符串标签一样。您可以将多个标签绑定到一个对象，如果要与另一个对象替换，则必须确保重新绑定所有这些标签。
您从此开始：
sys.modules['child002']
-> module object created from child002.py
-> module.__dict__ (the module globals)
-> module.__dict__['calculation_two']
|
|
+--> function object named calculation_two
|
|
-> module.__dict__['calculation_two']
-> module.__dict__ (the module globals)
-> module object for child003.py
sys.modules['child003']
，然后当您重新加载child002模块时，Python将所有现有的全局变量替换为新对象，因此您现在拥有：
sys.modules['child002']
-> module object created from child002.py
-> module.__dict__ (the module globals)
-> module.__dict__['calculation_two']
|
|
+--> *new* function object named calculation_two
+--> *old* function object named calculation_two
|
|
-> module.__dict__['calculation_two']
-> module.__dict__ (the module globals)
-> module object for child003.py
sys.modules['child003']
因为calculation_two模块对象中的child003引用是一个独立的标签。
您必须手动替换该标签：
calculation_two = reload(sys.modules["child002"]).calculation_two
child003.calculation_two = calculation_two
或者您不能直接引用calculation_two，而只能引用child002模块：
import child002
# ...
def calculation_three():
# ...
result = child002.calculation_two(3)
此时您具有以下关系：
sys.modules['child002']
-> module object created from child002.py
^ -> module.__dict__ (the module globals)
| -> module.__dict__['calculation_two']
| |
| |
| +--> function object named calculation_two
|
|
+------------+
|
|
-> module.__dict__['child002']
-> module.__dict__ (the module globals)
-> module object for child003.py
sys.modules['child003']
我建议您阅读Ned Batchelder's explanation of Python names and values以获得另一种观点。