在文件中附加每一行

Question

I want to append each line in file in python For example:

File.txt

Is it funny?
Is it dog?

Expected Result

Is it funny? Yes
Is it dog? No

Assume that YES, No is given. I am doing in this way:

with open('File.txt', 'a') as w:
            w.write("Yes")

But it appends at the end of file. Not on every line.

Edit 1

with open('File.txt', 'r+') as w:
            for line in w:
                w.write(line + " Yes ")

This is giving the result

Is it funny?
Is it dog?Is it funny?
 Yes Is it dog? Yes 

I do not need this.It is adding new line with appended string. I need

Is it funny? Yes
Is it dog? No

Answer 1

You can write to a tempfile then replace the original:

from tempfile import NamedTemporaryFile
from shutil import move
data = ["Yes", "No"]
with open("in.txt") as f, NamedTemporaryFile("w",dir=".", delete=False) as temp:
    # pair up lines and each string
    for arg, line in zip(data, f):
        # remove the newline and concat new data
        temp.write(line.rstrip()+" {}\n".format(arg))

# replace original file
move(temp.name,"in.txt")

You could also use fileinput with inplace=True :

import fileinput
import sys
for arg, line in zip(data, fileinput.input("in.txt",inplace=True)):
    sys.stdout.write(line.rstrip()+" {}\n".format(arg))

Output:

Is it funny? Yes
Is it dog? No

Answer 2

Here is a solution that copies existing file content to a temp file. Modifies it as per needs. Then writes back to original file. Inspiration from here

import tempfile    

filename = "c:\\temp\\File.txt"

#Create temporary file
t = tempfile.NamedTemporaryFile(mode="r+")

#Open input file in read-only mode
i = open(filename, 'r')

#Copy input file to temporary file
for line in i:
  #For "funny" add "Yes"
  if "funny" in line:
      t.write(line.rstrip() + "Yes" +"\n")
  #For "dog" add "No"
  elif "dog" in line:
      t.write(line.rstrip() + "No" +"\n")


i.close() #Close input file

t.seek(0) #Rewind temporary file

o = open(filename, "w")  #Reopen input file writable

#Overwriting original file with temp file contents          
for line in t:
   o.write(line)  

t.close() #Close temporary file