469,285 Members | 2,588 Online
Bytes | Developer Community
New Post

Home Posts Topics Members FAQ

Post your question to a community of 469,285 developers. It's quick & easy.

local variable referenced before assignment


Quick question, probably quite a simple matter. Take the follow start of
a method:
def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment

I thought I'd assigned it in the "(tightestOwner, logMsg) = item" line -
so in the python interpreter complaining about the fact this assignment
might not go well?

Thanks!
Oct 25 '07 #1
9 16750
On 2007-10-25, Pete Bartonly <no**@try.invalidwrote:
>
Quick question, probably quite a simple matter. Take the follow start of
a method:
def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment
This should work, are you sure you didn't make a typo in one of the names?

Another way to make this fail would be when the if-condition is outside
the loop (is the indentation correct in your code?).

A short demontration:
>>def r(fnr):
.... for item in fnr:
.... w,m = item
.... if m == 2:
.... print w
....
>>fnr = [(1,2), (3,4)]
r(fnr)
1

With respect to compactness and style, you can move your multi-assignment
statement in the for loop, as in

for tightestOwner, logMsg in filesNeedingReview:

Also, brackets around conditions (in the if) are not needed, and comparing
against None is usually done with 'is' or 'is not' instead of '==' or '!='.
The result is then

if logMsg is not None:

I thought I'd assigned it in the "(tightestOwner, logMsg) = item" line -
so in the python interpreter complaining about the fact this assignment
might not go well?
No, you'd get an error at that point in that case.
Sincerely,
Albert
Oct 25 '07 #2
Pete Bartonly wrote:
Quick question, probably quite a simple matter. Take the follow start of
a method:
def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment

I thought I'd assigned it in the "(tightestOwner, logMsg) = item" line -
so in the python interpreter complaining about the fact this assignment
might not go well?
My crystal ball tells me that you are not posting the actual code where
for... and if... are indented to the same level. This triggers the error
when review() is called with an empty sequence.

Please remember to copy and paste both code and traceback next time.

Peter
Oct 25 '07 #3
On Oct 25, 10:02 am, Pete Bartonly <n...@try.invalidwrote:
Quick question, probably quite a simple matter. Take the follow start of
a method:

def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:

This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment
Check your indentation?
Seems to me that you might really have:

def review(...):
for ...:
....
if (logMsg...):
....

HTH

--
Arnaud
Oct 25 '07 #4
On 25/10/2007, A.T.Hofkamp <ha*@se-162.se.wtb.tue.nlwrote:
On 2007-10-25, Pete Bartonly <no**@try.invalidwrote:
Also, brackets around conditions (in the if) are not needed, and comparing
against None is usually done with 'is' or 'is not' instead of '==' or '!='.
The result is then

if logMsg is not None:
Or just
>> if logMsg:
do_something()

:)
Oct 25 '07 #5
On 2007-10-25, Tim Williams <td*******@gmail.comwrote:
On 25/10/2007, A.T.Hofkamp <ha*@se-162.se.wtb.tue.nlwrote:
>On 2007-10-25, Pete Bartonly <no**@try.invalidwrote:
>
Also, brackets around conditions (in the if) are not needed, and comparing
against None is usually done with 'is' or 'is not' instead of '==' or '!='.
The result is then

if logMsg is not None:

Or just
>>> if logMsg:
do_something()

:)
That is not the same.

If logMsg is 0, False, or empty string, the second variant
would be False and not True.

Albert
Oct 25 '07 #6
A.T.Hofkamp wrote:
On 2007-10-25, Pete Bartonly <no**@try.invalidwrote:
>Quick question, probably quite a simple matter. Take the follow start of
a method:
def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment

This should work, are you sure you didn't make a typo in one of the names?
Nope, the above is verbatim. This is why I'm so confused. It should
work! I'm editing in emacs, and the indents are tab chars. I've
re-indented the indents using 'tab' key - same result.

The entire error output is this:

Traceback (most recent call last):
File "checkCode.py", line 602, in ?
analyseFiles(tempDir)
File "checkCode.py", line 448, in analyseFiles
analyseFilesInARepos(startDir, f)
File "checkCode.py", line 590, in analyseFilesInARepos
makeReport(projName, filesNeedingReview, filesFailedReview)
File "checkCode.py", line 422, in makeReport
for logInfo in logMsg.changed_paths:
UnboundLocalError: local variable 'logMsg' referenced before assignment

I'm rather stuck at what to try next!

thanks.
Pete


>
Another way to make this fail would be when the if-condition is outside
the loop (is the indentation correct in your code?).

A short demontration:
>>>def r(fnr):
... for item in fnr:
... w,m = item
... if m == 2:
... print w
...
>>>fnr = [(1,2), (3,4)]
r(fnr)
1

With respect to compactness and style, you can move your multi-assignment
statement in the for loop, as in

for tightestOwner, logMsg in filesNeedingReview:

Also, brackets around conditions (in the if) are not needed, and comparing
against None is usually done with 'is' or 'is not' instead of '==' or '!='.
The result is then

if logMsg is not None:

>I thought I'd assigned it in the "(tightestOwner, logMsg) = item" line -
so in the python interpreter complaining about the fact this assignment
might not go well?

No, you'd get an error at that point in that case.
Sincerely,
Albert
Oct 25 '07 #7
A.T.Hofkamp wrote:
On 2007-10-25, Pete Bartonly <no**@try.invalidwrote:
>Quick question, probably quite a simple matter. Take the follow start of
a method:
With respect to compactness and style, you can move your multi-assignment
statement in the for loop, as in
[snip]

Btw, thanks for the tips on style too!
Pete
Oct 25 '07 #8
Peter Otten wrote:
Pete Bartonly wrote:
>Quick question, probably quite a simple matter. Take the follow start of
a method:
def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment

I thought I'd assigned it in the "(tightestOwner, logMsg) = item" line -
so in the python interpreter complaining about the fact this assignment
might not go well?

My crystal ball tells me that you are not posting the actual code where
for... and if... are indented to the same level.
I am! See my other reply just now.

Here it the code again, directly cut and pasted from emacs:

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
if (not tightestOwner in emailListForReviewers):
emailListForReviewers.append(tightestOwner)


This triggers the error
when review() is called with an empty sequence.

Please remember to copy and paste both code and traceback next time.
Sorry 'bout that. The traceback I forgot is:

Traceback (most recent call last):
File "checkCode.py", line 599, in ?
analyseFiles(tempDir)
File "checkCode.py", line 445, in analyseFiles
analyseFilesInARepos(startDir, f)
File "checkCode.py", line 587, in analyseFilesInARepos
makeReport(projName, filesNeedingReview, filesFailedReview)
File "checkCode.py", line 419, in makeReport
for logInfo in logMsg.changed_paths:
UnboundLocalError: local variable 'logMsg' referenced before assignment
Pete
Oct 25 '07 #9
Pete Bartonly wrote:
>
Quick question, probably quite a simple matter. Take the follow start of
a method:
def review(filesNeedingReview):

for item in filesNeedingReview:
(tightestOwner, logMsg) = item

if (logMsg != None):
for logInfo in logMsg.changed_paths:
This generates the error:

UnboundLocalError: local variable 'logMsg' referenced before assignment

I thought I'd assigned it in the "(tightestOwner, logMsg) = item" line -
so in the python interpreter complaining about the fact this assignment
might not go well?

Thanks!
Argh! Mea culpa everyone!
Turns out that there is a similar few lines of code later on in the
code. I was confusing which was which. (I was using meta-x goto-line but
then looking at the wrong but somehow, as it appeared on the same screen
in emacs.)
So the error was occuring at a similar line in the code, but one at
whihc logMsg *wasn't* being set beforehand.

Sorry all, thanks for your help, appreciate it!
Pete

Oct 25 '07 #10

This discussion thread is closed

Replies have been disabled for this discussion.

Similar topics

166 posts views Thread by Graham | last post: by
2 posts views Thread by silverburgh.meryl | last post: by
3 posts views Thread by Hari Sekhon | last post: by
9 posts views Thread by Pyenos | last post: by
8 posts views Thread by Sullivan WxPyQtKinter | last post: by
2 posts views Thread by Matt Nordhoff | last post: by
1 post views Thread by CARIGAR | last post: by
reply views Thread by zhoujie | last post: by
reply views Thread by suresh191 | last post: by
By using this site, you agree to our Privacy Policy and Terms of Use.