I'm sorry if this is silly question but I have no much Python experience
I have function for comparing files
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()
I want to print function output to a text file
result=compare_files("1.txt", "2.txt")
print (result)
Line changed:Line-1-aaaaa
Line added:Line-2-sss
None
i tried following:
f = open('changes.txt', 'w')
f.write(str(result))
f.close
but only None is printed to changes.txt
I'm using "workaround" sys.stdout but wonder is there any other way instead of redirecting print output.
If in function output I specify return instead of print then I'm getting only first output line (Line changed:Line-1-aaaaa) to changes.txt
Because you are not returning anything by default the function returns None so that is reflected in your changes.txt file. you can create a variable that stores the output that you wanted and returns it.
def compare_files(file1, file2):
fname1 = file1
fname2 = file2
# Open file for reading in text mode (default mode)
f1 = open(fname1)
f2 = open(fname2)
output_string = ""
# 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)
output_string += "Line added:Line-%d" % line_no + "-" + f1_line + "\n"
# otherwise output the line on file1 and mark it with > sign
elif f1_line != '':
print("Line changed:Line-%d" % line_no + "-" + f1_line)
output_string += "Line changed:Line-%d" % line_no + "-" + f1_line +"\n"
########### 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)
output_string += "Line removed:Line-%d" % line_no + "-" + f1_line +"\n"
# 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()
return output_string