Python将函数输出写入文件

Question

如果这是个愚蠢的问题，我很抱歉，但我没有太多 Python 经验

我有比较文件的功能

def compare_files(file1, file2):
    fname1 = file1
    fname2 = file2

    # Open file for reading in text mode (default mode)
    f1 = open(fname1)
    f2 = open(fname2)
    # Print confirmation
    #print("-----------------------------------")
    #print("Comparing files ", " > " + fname1, " < " +fname2, sep='\n')
    #print("-----------------------------------")

    # Read the first line from the files
    f1_line = f1.readline()
    f2_line = f2.readline()

    # Initialize counter for line number
    line_no = 1

    # Loop if either file1 or file2 has not reached EOF

    while f1_line != '' or f2_line != '':

       # Strip the leading whitespaces
      f1_line = f1_line.rstrip()
      f2_line = f2_line.rstrip()

      # Compare the lines from both file
      if f1_line != f2_line:

         ########## If a line does not exist on file2 then mark the output with + sign
        if f2_line == '' and f1_line != '':
            print ("Line added:Line-%d" % line_no + "-"+ f1_line)
         #otherwise output the line on file1 and mark it with > sign
        elif f1_line != '':
            print ("Line changed:Line-%d" % line_no + "-"+ f1_line)


        ########### If a line does not exist on file1 then mark the output with + sign
        if f1_line == '' and f2_line != '':
            print ("Line removed:Line-%d" % line_no + "-"+ f1_line)
          # otherwise output the line on file2 and mark it with < sign
         #elif f2_line != '':
            #print("<", "Line-%d" %  line_no, f2_line)

         # Print a blank line
         #print()

    #Read the next line from the file
      f1_line = f1.readline()
      f2_line = f2.readline()
      #Increment line counter
      line_no += 1

    # Close the files
    f1.close()
    f2.close()

我想将函数输出打印到文本文件

result=compare_files("1.txt", "2.txt")

print (result)
Line changed:Line-1-aaaaa
Line added:Line-2-sss
None

我试过以下:

f = open('changes.txt', 'w')

f.write(str(result))

f.close

但只有 None 被打印到 changes.txt

我正在使用“解决方法”sys.stdout，但想知道是否有其他方法可以代替重定向打印输出。

如果在函数输出中我指定 return 而不是 print 那么我只会将第一行输出 (Line changed:Line-1-aaaaa) 更改为 changes.txt

Answer 1

您的“compare_files”函数不会返回任何内容，因此不会向文件写入任何内容。使函数“返回”成为某种东西，它应该可以工作。