How to while loop until the end of a file in Python without checking for empty line

Question

I m writing an assignment to count the number of vowels in a file  currently in my class we have only been using code like this to check for the end of a file   vowel 0 f open  filename txt   r  encoding  utf-8    line f readline   strip   while line          for j in range  len line            if line j  isvowel                vowel  1      line f readline   strip     But this time for our assignment the input file given by our professor is an entire essay  so there are several blank lines throughout the text to separate paragraphs and whatnot  meaning my current code would only count until the first blank line   Is there any way to check if my file has reached its end other than checking for if the line is blank  Preferably in a similar fashion that I have my code in currently  where it checks for something every single iteration of the while loop  Thanks in advance

User · Answer

I discovered while following the above suggestions that  for line in f  does not work for a pandas dataframe  not that anyone said it would  because the end of file in a dataframe is the last column  not the last row  for example if you have a data frame with 3 fields  columns  and 9 records  rows   the for loop will stop after the 3rd iteration  not after the 9th iteration  Teresa

User · Answer

Find end position of file   f   open  file txt   r   f seek 0 2   Jumps to the end f tell       Give you the end location  characters from start  f seek 0     Jump to the beginning of the file again   Then you can to   if line       and f tell      endLocation     break

User · Answer

Don t loop through a file this way  Instead use a for loop   for line in f      vowel    sum ch isvowel   for ch in line    In fact your whole program is just   VOWELS     A   E   I   O   U   a   e   i   o   u     I m assuming this is what isvowel checks  unless you re doing something   fancy to check if  y  is a vowel with open  filename txt   as f      vowel   sum ch in VOWELS for line in f for ch in line strip      That said  if you really want to keep using a while loop for some misguided reason   while True      line   f readline   strip       if line                  either end of file or just a blank line                we ll assume EOF  because we don t have a choice with the while loop          break

User · Answer

for line in f  reads all file to a memory  and that can be a problem  My offer is to change the original source by replacing stripping and checking for empty line  Because if it is not last line - You will receive at least newline character in it    n    And   strip    removes it  But in last line of a file You will receive truely empty line  without any characters  So the following loop will not give You false EOF  and You do not waste a memory  with open  quot blablabla txt quot    quot r quot   as fl in     while True        line   fl in readline            if not line              break        line   line strip           do what You want

[python] How to while loop until the end of a file in Python without checking for empty line?

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