What to do if I want to handle different errors in try except block?

Python Help
1

What to do if I want to handle different errors, and each error differently in try-except block?
I’m fresh to python so I don’t know

2

You can have multiple except. See this example

class B(Exception):
    pass

class C(B):
    pass

class D(C):
    pass

for cls in [B, C, D]:
    try:
        raise cls()
    except D:
        print("D")
    except C:
        print("C")
    except B:
        print("B")

from the documentation

1 Like
3

oh, thank you so much sir/ma’am, I didn’t knew you could have multiple except blocks attached to one try block, thank you so much :grinning:

1 Like
4

They’re matched in order, so keep in mind that you want to provide the
more-specific exceptions first. And you can also test things if just the
exception type is not specific enough. Example:

 try:
   old_xattr_value_b = os.getxattr(fspath, xattr_name_b)
 except OSError as e:
   if e.errno not in (errno.ENOTSUP, errno.ENOENT, errno.ENODATA):
     raise
   old_xattr_value_b = None

Here I want to handle an OSError for “not supported”, “file not found”
and “no data”. But not other OSErrors (eg “permission denied”). So
I’m looking at the specifics of the OSError. If it isn’t one of the
ones I expect, I issue a bare raise statement to reraise the
exception, effectively “uncatching” it.

On the more-specific side of things, these days one can catch “file not
found” and several other specific OSError types, so the above could
look like:

 try:
   old_xattr_value_b = os.getxattr(fspath, xattr_name_b)
 except FileNotFoundError: # aka OSError ENOENT
   old_xattr_value_b = None
 except OSError as e:
   if e.errno not in (errno.ENOTSUP, errno.ENODATA):
     raise
   old_xattr_value_b = None

The FileNotFoundError is a subclass of OSError. Not all OSError
flavours have a specific named subclass.

Again, note that we’re catching the FileNotFoundError before the
OSError.

5

Also have the ability to accept multiple exception types at once:

except (OSError, ValueError) as ex:
    ...