Question

The simplest built-in exception as below:

>>> 1/0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ZeroDivisionError: division by zero

整个报刊都例外。

Define function f1 and not to define myException:

def f1():
    try:
        print(1/0)
    except:
        raise myException( my exception )

Call f1():

>>> f1()
Traceback (most recent call last):
  File "<stdin>", line 3, in f1
ZeroDivisionError: division by zero

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 5, in f1
NameError: name  myException  is not defined

当胎儿

Traceback (most recent call last):
  File "<stdin>", line 3, in f1
ZeroDivisionError: division by zero

thrown out,exception of print(1/0) is handled as we have seen that in the beginning.
Why the statement in the middle line is During handling of the above exception, another exception occurred: ,instead of After handling of the above exception, another exception occurred:?
What is above exception in the statement During handling of the above exception?It points to try ... except structure in f1 ,instead of exception resulted by 1/0?
If above exception points to exception resulted by 1/0,then After handling of the above exception, another exception occurred is better to describe all the exceptions here!

Answer 1

这是MyException时,python将自动在其_cause_上添加目前的例外情况。

因此,你看到这两种例外情况都列出。您提出的观点和载于_cause_的属性。让我们以多种方式,特别是“从”例外,对例外情况进行专门处理。通常,

raise myException from OtherException

更具体地说,为了完全禁止原始例外,将其排除在<条码>_cause_属性之外,从<条码>中删除:

raise myException from None

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