如果文件的行为空，如何跳过文件的行 [英] how to skip over lines of a file if they are empty

问题描述

在python 3中编程：
这是我的第一个程序涉及文件。我需要忽略注释行（以＃开头）和空白行，然后拆分这些行使它们是可迭代的，但我不断得到和IndexError消息，说字符串索引超出范围，程序崩溃在空白行。

Program in python 3: This is my first program involving files. I need to ignore comment lines (start with #) and blank lines, and then split the lines so they are iterable, but I keep on getting and IndexError message that says string index out of range, and the program crashes on the blank line.

import os.path

def main():

endofprogram = False
try:
    #ask user to enter filenames for input file (which would 
    #be animals.txt) and output file (any name entered by user)
    inputfile = input("Enter name of input file: ")

    ifile = open(inputfile, "r", encoding="utf-8")
#If there is not exception, start reading the input file        
except IOError:
    print("Error opening file - End of program")
    endofprogram = True

else:
    try:     
        #if the filename of output file exists then ask user to 
        #enter filename again. Keep asking until the user enters 
        #a name that does not exist in the directory        
        outputfile = input("Enter name of output file: ")
        while os.path.isfile(outputfile):
            if True:
                outputfile = input("File Exists. Enter name again: ")        
        ofile = open(outputfile, "w")

        #Open input and output files. If exception occurs in opening files in 
        #read or write mode then catch and report exception and 
        #exit the program
    except IOError:
        print("Error opening file - End of program")
        endofprogram = True            

if endofprogram == False:
    for line in ifile:
        #Process the file and write the result to display and to the output file
        line = line.strip()
        if line[0] != "#" and line != None:
            data = line.split(",")
            print(data)                
ifile.close()
ofile.close()
main() # Call the main to execute the solution

推荐答案

您的问题来自空行不是 None ，因为你似乎假设。以下是可能的修正：

Your problem comes from the fact that empty lines are not None, as you seem to assume. The following is a possible fix:

for line in ifile:
    line = line.strip()
    if not line:  # line is blank
        continue
    if line.startswith("#"):  # comment line
        continue
    data = line.split(',')
    # do stuff with data

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