"list index out of range" with a loop [closed]

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I am running the below code it works like a charm for few days and now I am facing the following error message: "list index out of range" related to:

for i in range(item_count, 0, -1):
 message = out_iter_folder.Items[i]

this code was running perfectly for weeks and I can fix it just by replacing the calculated item_count value with the same one -1 not really sure why it worked and stopped working ?

many thanks :) !

import win32com.client
EMAIL_ACCOUNT = 'Enter your email address' # e.g. '[email protected]'
ITER_FOLDER = 'Enter the Outlook folder name which emails you would like to iterate through' # e.g. 
'IterationFolder'
MOVE_TO_FOLDER = 'Enter the Outlook folder name where you move the processed emails' # e.g 
'ProcessedFolder'
SAVE_AS_PATH = 'Enter the path where to dowload attachments' # e.g.r'C:\DownloadedCSV'
EMAIL_SUBJ_SEARCH_STRING = 'Enter the sub-string to search in the email subject' # e.g. 'Email to 
download'
def find_download_csv_in_outlook():
 out_app = win32com.client.gencache.EnsureDispatch("Outlook.Application")
 out_namespace = out_app.GetNamespace("MAPI")
 out_iter_folder = out_namespace.Folders[EMAIL_ACCOUNT].Folders[ITER_FOLDER]
 out_move_to_folder = out_namespace.Folders[EMAIL_ACCOUNT].Folders[MOVE_TO_FOLDER]
 char_length_of_search_substring = len(EMAIL_SUBJ_SEARCH_STRING)
 # Count all items in the sub-folder
 item_count = out_iter_folder.Items.Count
 if out_iter_folder.Items.Count > 0:
 for i in range(item_count, 0, -1):
 message = out_iter_folder.Items[i]
 # Find only mail items and report, note, meeting etc items
 if '_MailItem' in str(type(message)):
 print(type(message))
 if message.Subject[0:char_length_of_search_substring] == EMAIL_SUBJ_SEARCH_STRING \
 and message.Attachments.Count > 0:
 for attachment in message.Attachments:
 if attachment.FileName[-3:] == 'csv':
 attachment.SaveAsFile(SAVE_AS_PATH + '\\' + attachment.FileName)
 message.Move(out_move_to_folder)
 else:
 print("No items found in: {}".format(ITER_FOLDER))
if __name__ == '__main__':
 find_download_csv_in_outlook()

• pho: Python list indices are zero-based. A list of length 4 has indices 0, 1, 2, and 3. You need to iterate from len(list) - 1 to zero (both inclusive), so you need to do range(len(list) - 1, -1, -1). See this similar recent question: stackoverflow.com/q/67593572/843953
• JonSG: Are you sure it worked? range(5, 0, -1) starts at 5 and ends at 1 and it is very likely that out_iter_folder.Items[i] is out of range on the first iteration since lists are 0-based and would expect indexes starting at 4 and ending at 0.
• John Coleman: I doubt that the code that you posted was working fine and then inexplicably stopped working. You must have introduced a bug in some edit.

Answer 1

The range will go from item_count(included) to 0(excluded). So, you have to loop it from item_count-1 to -1 as the indexing of the list starts from 0 not 1.

for i in range(item_count-1, -1, -1):
 message = out_iter_folder.Items[i]

OR

for i in reversed(range(0,item_count)):
 message = out_iter_folder.Items[i]