screen shot
hi, I am trying to run this python code for twitter scraping. as it is shown in the screenshot, it gives me a syntax error that I can't figure out. here is the whole code:
print ('Filtering the public timeline for track="%s"' % (q,))
twitter_stream = twitter.TwitterStream(auth=twitter_api.auth)
stream = twitter_stream.statuses.filter(track=q)
for tweet in stream:
try:
if tweet['truncated']:
tweet_text = tweet['extended_tweet']['full_text']
else:
tweet_text = tweet['text']
# write the values to file
csvwriter.writerow([
tweet['created_at'],
getVal(tweet['user']['screen_name']),
getVal(tweet_text),
getVal(tweet['user']['location']),
tweet['user']['statuses_count'],
tweet['user']['followers_count'],
tweet['user']['friends_count'],
tweet['user']['created_at']
])
# print something to the screen, mostly so we can see what is going on...
print (tweet['user']['screen_name'].encode('utf-8'), tweet['text'].encode('utf-8'))
except Exception, err:
print err
pass
I can only assume you are running this using Python 3 and not 2.
This question explains that the format you've used for the except statement would be wrong in that case.
The TL;DR of that post is:
switch the comma to as: except Exception as err:
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'm putting errors in Try and Except, but I'm having trouble with 2 types of errors. I'll give you an example of what I need. This except with Valure Error works fine, because I know the error is called ValueError, so:
#ONLY EXAMPLE
except ValueError:
return "FAILED"
EXCEPT ERROR N.1
The question I ask you is: how should I write for the following error? It consists of the wrong name of an html class when scraping. I wrote selenium.common.exceptions.NoSuchElementException, but the error search does not work (the script does not open at all)
except selenium.common.exceptions.NoSuchElementException:
return "FAILED"
EXCEPT ERROR N.2
Same thing for the database insert error. I want to make sure that if 0 records are saved in the database then I have an error. I tried to write like this, but it's not good:
except records_added_Results = records_added_Results = + 0:
return "FAILED"
I wrote this because I have this code for the insertion in the database. It works correctly, I am writing it just to make you understand:
con = sqlite3.connect('/home/mypc/Scrivania/folder/Database.db')
cursor = con.cursor()
records_added_Results = 0
Values = ((SerieA_text,), (SerieB_text,)
sqlite_insert_query = 'INSERT INTO ARCHIVIO_Campionati (Nome_Campionato) VALUES (?);'
count = cursor.executemany(sqlite_insert_query, Values)
con.commit()
print("Record inserted successfully ", cursor.rowcount)
records_added_Results = records_added_Results + 1
cursor.close()
How should I write? Thank you
Import the exception before you try to catch it. Add this line to your imports:
from selenium.common.exceptions import NoSuchElementException
Then you can simply do:
try:
#code that could raise the NoSuchElementException
except NoSuchElementException:
#exception handling
For the other exception, it looks like you're trying to raise an exception. Consider something like this:
if records_added_Results == 0:
raise ValueError("error message")
i'm stuck with my simple code, i'm a newbie for coding.. I'm using python and
In my list i have bad values that made exceptions (httperror : 404) . I want to ignore this exceptions and continue my loop. But with my code, the print("Http error") loop again and again. I don't know how to pass this exception to loop the entire code again.
while i < len(list_siret):
try :
data = api.siret(list_sirets[i]).get()
str_datajs = json.dumps(data, indent= 4)
a_json = json.loads(str_datajs)
i +=1
print("test1", i ,str_datajs)
except urllib.error.URLError :
print("Http error")
pass
Since you have print("Http error") inside the except block, it will be executed every time the exception occurs.
Consider the more idiomatic approach below:
for siret in list_siret:
try:
data = api.siret(siret).get()
except urllib.error.URLError:
continue
str_datajs = json.dumps(data, indent=4)
a_json = json.loads(str_datajs)
print("test1", i ,str_datajs)
We iterate directly over list_siret without needing to index into it and manually manage i, and instead of passing we just move to the next element in the list in case an exception was raised.
I am a relative python newbie and I am getting confused with how to properly handle exceptions. Apologies for the dumb question.
In my main() I iterate through a list of dates and for each date I call a function, which downloads a csv file from a public web server. I want to properly catch exceptions for obvious reasons but especially because I do not know when the files of interest will be available for download. My program will execute as part of a cron job and will attempt to download these files every 3 hours if available.
What I want is to download the first file in the list of dates and if that results in a 404 then the program shouldn't proceed to the next file because the assumption is if the oldest date in the list is not available then none of the others that come after it will be available either.
I have the following python pseudo code. I have try/except blocks inside the function that attempts to download the files but if an exception occurred inside the function how do I properly handle it in the main() so I can make decisions whether to proceed to the next date or not. The reason why I created a function to perform the download is because I want to re-use that code later on in the same main() block for other file types.
def main():
...
...
# datelist is a list of date objects
for date in datelist:
download_file(date)
def download_file(date):
date_string = str(date.year) + str(date.strftime('%m')) + str(date.strftime('%d'))
request = HTTP_WEB_PREFIX+ date_string + FILE_SUFFIX
try:
response = urllib2.urlopen(request)
except urllib2.HTTPError, e:
print "HTTPError = " + str(e)
except urllib2.URLError, e:
print "URLError = " + str(e)
except httplib.HTTPException, e:
print "HTTPException = " + str(e)
except IOError:
print "IOError = " + str(e)
except Exception:
import traceback
print "Generic exception: " + traceback.format_exc()
else:
print "No problem downloading %s - continue..." % (response)
try:
with open(TMP_DOWNLOAD_DIRECTORY + response, 'wb') as f:
except IOError:
print "IOError = " + str(e)
else:
f.write(response.read())
f.close()
The key concept here is, if you can fix the problem, you should trap the exception; if you can't, it's the caller's problem to deal with. In this case, the downloader can't fix things if the file isn't there, so it should bubble up its exceptions to the caller; the caller should know to stop the loop if there's an exception.
So let's move all the exception handling out of the function into the loop, and fix it so it craps out if there's a failure downloading the file, as the spec requires:
for date in datelist:
date_string = str(date.year) +
str(date.strftime('%m')) +
str(date.strftime('%d'))
try:
download_file(date_string)
except:
e = sys.exc_info()[0]
print ( "Error downloading for date %s: %s" % (date_string, e) )
break
download_file should now, unless you want to put in retries or something like that, simply not trap the exceptions at all. Since you've decoded the date as you like in the caller, that code can come out of download_file as well, giving the much simpler
def download_file(date_string):
request = HTTP_WEB_PREFIX + date_string + FILE_SUFFIX
response = urllib2.urlopen(request)
print "No problem downloading %s - continue..." % (response)
with open(TMP_DOWNLOAD_DIRECTORY + response, 'wb') as f:
f.write(response.read())
f.close()
I would suggest that the print statement is superfluous, but that if you really want it, using logger is a more flexible way forward, as that will allow you to turn it on or off as you prefer later by changing a config file instead of the code.
From my understanding of your question... you should just insert code into the except blocks that you want to execute when you encounter the particular exception. You don't have to print out the encountered error, you can do whatever you feel is necessary when it is raised... provide a popup box with information/options or otherwise direct your program to the next step. Your else section should isolate that portion, so it will only execute if none of your exceptions are raised.
I am having trouble getting this to work correctly (obviously) - I am ALMOST there, and I have a good idea of WHY it is not working - just not sure how to make it work.
This is suppose to attempt to read a file into memory, if it fails it goes to the "except" clause of the block of code (that part is 'duh'). The error file prints: "<main.DebugOutput instance at 0x04021EB8>". What I want it to do is print the actual Error. Like a FileIOError or TraceBackError or whatever it is to that error file. This is just the beginning stages and I plan to add things like date stamps and to have it append, not write/create - I just need the actual error printed to the file. Advice?
import os, sys
try:
myPidFile = "Zeznadata.txt"
myOpenPID_File = open(myPidFile, "r") #Attempts to open the file
print "Sucessfully opened the file: \"" + myPidFile + "\"."
except:
print "This file, \"" + myPidFile + "\", does not exist. Please check the file name and try again. "
myFileErr = open("PIDErrorlog.txt", "w")
myStdError = str(sys.stderr)
myFileErr.write(myStdError)
myFileErr.close()
print "\nThis error was logged in the file (and stored in the directory): "
First, you should use a logging library. It will help you deal with different logging levels (info/warn/error), timestamps and more.
http://docs.python.org/library/logging.html
Second, you need to catch the error, and then you can log details about it. This example comes from the Python documentation.
import sys
try:
f = open('myfile.txt')
s = f.readline()
i = int(s.strip())
except IOError as (errno, strerror):
print "I/O error({0}): {1}".format(errno, strerror)
except ValueError:
print "Could not convert data to an integer."
except:
print "Unexpected error:", sys.exc_info()[0]
raise
See how it catches an IOError and assigns the error number and error message to variables? You can have an except block for each type of error you want to deal with. In the last (generic error) block, it uses sys.exc_info()[0] to get the error details.
http://docs.python.org/tutorial/errors.html
the problem is here:
myStdError = str(sys.stderr)
myFileErr.write(myStdError)
sys.stderr is a file-like interface defined in POSIX standards, called standard error, not "error text" that you can write to a file. So what you (probably) wanted to do is:
sys.stderr = myFileErr
This is the python equivalent to python your_python_sctipt.py 2> PIDErrorLog.txt in unix shell.
Use the logging module. The logging module have exception formatters that will help you print exceptions in a pretty way.
http://docs.python.org/library/logging.html
Like Kimvais says, your problem is:
myStdError = str(sys.stderr)
myFileErr.write(myStdError)
sys.stderr is a file handle to stderr (stdout is what print writes to).
You should do something like:
try:
...open file...
except IOError as (errno, strerror):
...open errfile...
errfile.write(strerror)
errfile.close()
Alison's answer is also very good and well written.