I am trying in Python.
try:
newbutton['roundcornerradius'] = buttondata['roundcornerradius']
buttons.append(newbutton)
buttons is a list. roundcornerradius is optional in buttondata.
Alas this gives
buttons.append(newbutton)
^ SyntaxError: invalid syntax
I just want to ignore the cases where roundcornerradius does not exist. I don't need any error reported.
why arent you using the except keyword
try:
newbutton['roundcornerradius'] = buttondata['roundcornerradius']
buttons.append(newbutton)
except:
pass
this will try the first part and if an error is thrown it will do the except part
you can also add the disered error you want to except a certain error like this
except AttributeError:
you can also get the excepted error by doing this:
except Exception,e: print str(e)
You should catch a try with exception:
try:
code may through exception
except (DesiredException):
in case of exception
Also you can use else with try if you need to populate new buttons only when try succeeds:
try:
newbutton['roundcornerradius'] = buttondata['roundcornerradius']
except KeyError:
pass
else:
buttons.append(newbutton)
single except: with no exception class defined will catch every exception raised which may not be desired in some cases.
Most probably you will get KeyError on your code but I am not sure.
See here for builtin exceptions:
http://docs.python.org/2/library/exceptions.html
You must close block with except or finally if using try.
try:
newbutton['roundcornerradius'] = buttondata['roundcornerradius']
except KeyError:
pass#omit raise if key 'roundcornerradius' does not exists
buttons.append(newbutton)
If you know default value for 'roundcornerradius' - you dont need no try ... except
newbutton['roundcornerradius'] = buttondata.get('roundcornerradius', DEFAULT_RADIUS)
buttons.append(newbutton)
Related
I am making a Reddit bot using PRAW and the code gives me the error that the exception is not iterable. Here is a simplification of my code:
try:
#something with praw that isn't relevant
except Exception as e: #this except error catches the APIexception, APIexpections in PRAW are a wide field of exceptions that dont't always have the same solution, so I scan the text for the error I'm looking for.
print(e)
if "keyword thats in the error" in e:
#fix the problem with the specific error
else:
print("Unkown APIExpection error")
This works fine for me, but when I run this code:
try:
#something
except Exception as e:
for character in e:
print(character)
#I also tried this
try:
#something
except Exception as e:
for character in str(e):
print(character)
#None of the above work but this is my actual code and what I need to do, anything that gets the above to work should work here too, I'm just letting you know this so that I don't get any other errors I have to ask another question for.
try:
#something
except Exception as e:
characterNum = 0
for character in e:
characterNum += 1
print(str(characterNum) + ": " + character)
It gives me a "TypeError: 'RedditAPIException' is not iterable", RedditAPIException can be ignore though as that's just the error I'm catching.
Convert the exception to string and then check in the if statement.
Change to => if "keyword thats in the error" in str(e):
I have this try block in my code :
try:
installation('isc-dhcp-server')
except:
print('Oops an error...')
sys.exit(8)
Here in a try/except block the sys.exit(8) will just exit this block and keep an error with code "8". This is just what I want. Now I want to use this except somehere else in a code to avoid somes parts link to this setup. How can I do that ?
I try to put the error in a variable with :
except Exception as NameofError:
And use NameofError with a if statement but this var is not defined in the local space (I think) so I can't use it.
Just initiate a variable before the try-catch block and assign the exception to it
caught_error = None
try:
# some error throwing func
except Exception as e:
caught_error = e
# your error handling code
print(caught_error)
Edit: However, if you still have sys.exit() in your catch block you probably won't have the chance to do anything to the exception given that your program will be terminated already.
I have written Python code which does some calculation. During this it converts string to float. However sometimes numeric string value may be empty that time its giving me valueError. I tried to keep that in try catch block however its going to another exception block as shown below.
try:
float(some value)
except Exception as ValueError:
print(error message)
except Exception as oserror:
print(mesage)
Its going to os error block instead of ValueError block
That's not how you capture exceptions.
try:
float(some value)
except ValueError as e:
print("here's the message", e.args)
except OSError as e:
print("here's a different message")
(Note, though, there's no instance when calling float would raise an OSError.)
How can I get more information on the type of exception error ?
For example, in the code below I know the exception is gonna be ZeroDivisionError.
try:
print(1/0)
except ZeroDivisionError:
print("Error")
But I want to be able to get the information on the type of error without having to define it. I saw this example somewhere but it generates syntax error for me.
try:
return int(var)
except ValueError, Argument:
print "The argument does not contain numbers\n", Argument
What I am mainly looking for is something like
try:
// Do something
except:
// Print out an information on the type of error
try:
# Do something
except Exception as e:
print(e)
You can replace Exception with ZeroDivisionError if you wish.
You can use stacktrace to get all the info about error.
https://docs.python.org/2/library/traceback.html
import stacktrace
try:
// Do something
except:
print(traceback.format_exc())
I'm a Python learner, trying to handle a few scenarios:
Reading a file.
Formatting Data.
Manipulating/Copying Data.
Writing a file.
So far, I have:
try:
# Do all
except Exception as err1:
print err1
#File Reading error/ File Not Present
except Exception as err2:
print err2
# Data Format is incorrect
except Exception as err3:
print err3
# Copying Issue
except Exception as err4:
print err4
# Permission denied for writing
The idea of implementing in this fashion is to catch the exact error for all different scenarios. I can do it in all separate try/except blocks.
Is this possible? And reasonable?
Your try blocks should be as minimal as possible, so
try:
# do all
except Exception:
pass
is not something you want to do.
The code in your example won't work as you expect it to, because in every except block you are catching the most general exception type Exception. In fact, only the first except block will ever be executed.
What you want to be doing is having multiple try/except blocks, each one responsible for as few things as possible and catching the most specific exception.
For example:
try:
# opening the file
except FileNotFoundException:
print('File does not exist')
exit()
try:
# writing to file
except PermissionError:
print('You do not have permission to write to this file')
exit()
However, sometimes it is appropriate to catch different types of exceptions, in the same except block or in several blocks.
try:
ssh.connect()
except (ConnectionRefused, TimeoutError):
pass
or
try:
ssh.connect()
except ConnectionRefused:
pass
except TimeoutError:
pass
As DeepSpace stated,
Your try blocks should be as minimal as possible.
If you want to achieve
try:
# do all
except Exception:
pass
Then you might as well do something like
def open_file(file):
retval = False
try:
# opening the file succesful?
retval = True
except FileNotFoundException:
print('File does not exist')
except PermissionError:
print('You have no permission.')
return retval
def crunch_file(file):
retval = False
try:
# conversion or whatever logical operation with your file?
retval = True
except ValueError:
print('Probably wrong data type?')
return retval
if __name__ == "__main__":
if open_file(file1):
open(file1)
if open_file(file2) and crunch_file(file2):
print('opened and crunched')
Yes this is possible.
Just say as example:
try:
...
except RuntimeError:
print err1
except NameError:
print err2
...
Just define the exact Error you want to intercept.