Error in try/except construction [duplicate] - python

This question already has an answer here:
Python try except else invalid syntax?
(1 answer)
Closed 6 years ago.
Im just sitting for 10 minutes staring at a simple piece of code, which I have copied from a guide and I can't understand why I am getting an error.
def transformation(x):
date_format = "%d/%m/%Y"
try:
a = dt.date(int(x[6:10]), int(x[3:5]), int(x[0:2]))
else:
a = dt.datetime.strptime(x, date_format)
finally:
return a
File "<ipython-input-91-f1f6fe70d542>", line 5
else:
^
SyntaxError: invalid syntax
Maybe this is just me... Whats wrong?
After adding except:
def transformation(x):
date_format = "%d/%m/%Y"
try:
a = dt.date(int(x[6:10]), int(x[3:5]), int(x[0:2]))
except pass
else:
a = dt.datetime.strptime(x, date_format)
finally:
return a
File "<ipython-input-93-c2285c857574>", line 5
except pass
^
SyntaxError: invalid syntax

You need an except clause to use else:
The try ... except statement has an optional else clause, which, when
present, must follow all except clauses
[Emphasis mine]

I just saw it from the python document page, so I'm just gonna quote what it says to you:
The try ... except statement has an optional else clause, which, when present, must follow all except clauses. It is useful for code that must be executed if the try clause does not raise an exception. For example:
for arg in sys.argv[1:]:
try:
f = open(arg, 'r')
except IOError:
print('cannot open', arg)
else:
print(arg, 'has', len(f.readlines()), 'lines')
f.close()

Related

Handle Exception in Python

Code:
genders=[]
for image in os.listdir('Face'):
try:
gender = int(image.split('_')[1])
except ValueError:
pass
genders.append(gender)
Trying to add int values of string in list.
Raises Value error
ValueError: invalid literal for int() with base 10: ''
so for example : imageName_1 get that one and add to a list. but sometimes after _ there is no number. so i want to catch that image and delete it but don't want to stop the iteration.
Maybe a small change in the code will work
genders=[]
for image in os.listdir('Face'):
try:
gender = int(image.split('_')[1])
genders.append(gender)
except ValueError:
pass
Using continue statement will allow you to continue iteration.
genders=[]
for image in os.listdir('Face'):
try:
gender = int(image.split('_')[1])
except ValueError:
continue
genders.append(gender)
import os
genders=[]
for image in os.listdir('Face'):
try:
genders.append(int(image.split('_')[1]))
except (ValueError, IndexError):
try:
os.remove(image)
except OSError:
pass
gender is defined in the try clause only, so you can't append it to genders, and you don't need to (because you want to delete the file), so this line should be in the try clause also:
genders=[]
for image in os.listdir('Face'):
try:
gender = int(image.split('_')[1])
genders.append(gender)
except ValueError:
# delete file
os.remove(image)

How to properly handle multiple Runtime errors?

Program description:
Program accepts a file name and a segment, consisting of two numbers (each divided by one space). Then it outputs all lines from existing file where their indicies lie within the given segment.
My solution:
import sys
try:
par = input("Input (<file> <low border of the segment> <high border of the segment>): ").split(' ')
print(17 * '-')
f = par[0]
f_lines = [line.strip("\n") for line in f if line != "\n"]
length = len(f_lines)
if (par == ''):
raise RuntimeError('Error: undefined')
if (par[2] == None) or (par[2] == ''):
raise RuntimeError('Error: segment is limited')
if ((par[1] and par[2]) == None) or ((par[1] and par[2]) == ''):
raise RuntimeError('Error: segment undefined')
if (int(par[2]) >= length):
raise RuntimeError('Error: segment can not be greater than length the amount of lines')
if (par[1] == ''):
a = 0
if (par[2] == ''):
b = 0
segment = [int(par[1]), (int(par[2]) + 1)]
with open(par[0]) as f:
data = f.read().splitlines()
for k in range(segment[0], segment[1]):
print(data[k])
except (FileNotFoundError, IOError, NameError):
print('[!] Error: your input is incorrect. The file may be missing or something else. \n[?] For further information see full error logs: \n',sys.exc_info())
except RuntimeError as e:
print(e)
Problem:
When I try running my program in different ways to test each of my Runtime errors I always get this message:
Traceback (most recent call last):
File "C:\Users\1\Desktop\IT\pycharm\sem_2.py", line 10, in <module>
if (par[2] == None) or (par[2] == ''):
IndexError: list index out of range
I cannot wrap my head around how can I properly handle multiple Runtime errors so they would display as a text message. I haven't found any solution to my question anywhere online, so I'm trying to ask here.
I will appreciate any help, thanks in advance.
Your code would catch FileNotFoundError, IOError, NameError and RuntimeError but what is actually thrown is IndexError and that is not handled.
You may want to add IndexError it to the first except block:
except (FileNotFoundError, IOError, NameError, IndexError):
print('[!] Error: input incorrect!') # ^^^^^^^^^^^^
or perhaps add another except block if you want a custom message for IndexError:
except (FileNotFoundError, IOError, NameError):
print('[!] Error: input incorrect!')
except IndexError:
print('[!] Error: IndexError just happened!')
By the way, the following will always be False because the code in parentheses will resolve to a bool first, which can either be True or False and these are obviously never equal to '' or None:
((par[1] and par[2]) == None) or ((par[1] and par[2]) == '')
You may way want to rewrite it to:
(par[1] is None and par[2] is None) or (par[1] == '' and par[2] == '')

Python -IndentationError: unexpected unindent (Making Reddit Bot) [duplicate]

This question already has answers here:
What should I do with "Unexpected indent" in Python?
(18 answers)
Closed 2 years ago.
IndentationError: unexpected unindent WHY? Here's my code:
from praw.models import MoreComments
import praw
import giris
import time
import os
def bot_login():
print("Loggin in...")
r = praw.Reddit(username = giris.username,
password = giris.password,
client_id = giris.client_id,
client_secret = giris.client_secret,
user_agent = "karton_bardak_bot")
print("Logged in!")
return r
info="""
\n
\n
\n
^(ben bot) \n
\n
^(bruh)
"""
subreddit=r.subreddit("shithikayeler")
def run_bot(r, comments_replied_to):
print("Obtaining 25 comments...")
for submission in subreddit.new():
toReply=True
for top_level_comment in submission.comments:
if isinstance(top_level_comment, MoreComments):
continue
if not submission.is_self:
toReply=False
if top_level_comment.author=="karton_bardak_bot" or submission.selftext=='':
toReply=False
print("PASSED "+ submission.url)
log.write("PASSED "+ submission.url+"\n")
if toReply:
try:
new=reply(submission.selftext, info)
submission.reply(new)
except Exception as e:
log.write("ERROR: " + str(e) + " on submission " + submission.url)
print("REPLIED "+ submission.url)
log.write("REPLIED "+submission.url+"\n")
try:
time.sleep(60)
r = bot_login
while True:
run_bot(r)
It says:
File "bot.py", line 57
r = bot_login
^
IndentationError: unexpected unindent
Why? I have checked a thousands times and I can't find the problem. Pls help.
Because you start a
try:
block with out giving it the needed
except:
part... exactly here:
try:
time.sleep(60)
r = bot_login
so it complains about r = bot_login being maliciously wrong indented.
The code either expects you to stay inside the try: indentation to add more code or ex-dent once and add the except ... : part of the statement followed by another indent for it`s code.
See python.org tutorial about handling exceptions

Python - try/except not working when variable assigned to sys.argv

I have this section in my code:
# I/O files
inp_arq = sys.argv[1]
out_arq = sys.argv[2]
pad_ref = "pad_ref03.fasta"
tes_mdl = "model_05_weights.best.hdf5"
and at the end:
try:
results_df.to_csv(out_arq,index = False)
print(f"File saved as: {out_arq}")
except IndexError:
print("No output file created")
If no file is passed in as out_arq (sys.argv[2]) it should run the script and print "No output file created" at the end. But I'm getting the "IndexError: list index out of range."
But if I comment out the "out_arq = sys.argv[2]" line and change the code to:
try:
results_df.to_csv(sys.argv[2],index = False)
print(f"File saved as: {sys.argv[2]}")
except IndexError:
print("No output file created")
It works and I got the message, but I'm not sure why. I'd like to have all my I/O file/vars at the begginig of the script, but with this one (out_arq) I can't.
How can I solve this? And why this happens?
If you look at the stack trace that is printed by the exception, you should see that the exception is raised on this line:
out_arq = sys.argv[2]
This is outside the try block, so the exception is not caught, and causes your program to terminate.
A solution is to check, before indexing the array, whether the element exists:
out_arq = sys.argv[2] if len(sys.argv) >= 3 else None
Then use if instead of try:
if out_arq:
results_df.to_csv(out_arq,index = False)
print(f"File saved as: {out_arq}")
else:
print("No output file created")

Python syntax error (in the interpreter) after a for loop

I'm running some python code (pasted in) from the console, and getting an unexpected result. Here's what the code looks like:
parentfound = False
structfound = False
instruct = False
wordlist = []
fileHandle = open('cont.h')
for line in fileHandle:
if line is "":
print "skipping blank line"
continue
if "}" in line:
instruct = False
index = line.index("}")
wordlist.append(word)
pass
try:
print wordlist
except Exception as e:
print str(e)
After the for loop, I'd like to print the wordlist. No matter what I do, I can't include anything outside the for loop. Here's the error I receive:
... if "}" in line:
... instruct = False
... index = line.index("}")
... wordlist.append(word)
... pass
... try:
File "<stdin>", line 10
try:
^
SyntaxError: invalid syntax
It occurs whether I type the code by hand into the terminal or if I paste it in. I'd appreciate any help you can offer. Thank you!
The ... prompt in the REPL means that it still hasn't finished the previous block. You will need to press Enter on an empty line to terminate it first.

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