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Write a program in Python 3.5 that reads a file, then writes a different file with the same text that was in the first one as well as more?

The exact question to this problem is:
*Create a file with a 20 lines of text and name it “lines.txt”. Write a program to read this a file “lines.txt” and write the text to a new file, “numbered_lines.txt”, that will also have line numbers at the beginning of each line.
Example:
Input file: “lines.txt”
Line one
Line two
Expected output file:
1 Line one
2 Line two
I am stuck, and this is what I have so far. I am a true beginner to Python and my instructor does not make things very clear. Critique and help much appreciated.
file_object=open("lines.txt",'r')
for ln in file_object:
print(ln)
count=1
file_input=open("numbered_lines.txt",'w')
for Line in file_object:
print(count,' Line',(str))
count=+1
file_object.close
file_input.close
All I get for output is the .txt file I created stating lines 1-20. I am very stuck and honestly have very little idea about what I am doing. Thank you

You have all the right parts, and you're almost there:
When you do
for ln in file_object:
print(ln)
you've exhausted the contents of that file, and you won't be able to read them again, like you try to do later on.
Also, print does not write to a file, you want file_input.write(...)
This should fix all of that:
infile = open("lines.txt", 'r')
outfile = open("numbered_lines.txt", 'w')
line_number = 1
for line in infile:
outfile.write(str(line_number) + " " + line)
infile.close()
outfile.close()
However, here is a more pythonic way to do it:
with open("lines.txt") as infile, open("numbered_lines.txt", 'w') as outfile:
for i, line in enumerate(infile, 1):
outfile.write("{} {}".format(i, line))

Good first try, and with that, I can go through your code and explain what you did right (or wrong)
file_object=open("lines.txt",'r')
for ln in file_object:
print(ln)
This is fine, though generally you want to put a space before and after assignments (you are assigning the results of open to file_object) and add a space after a,` when separating arguments, so you might want to write that like so:
file_object = open("lines.txt", 'r')
for ln in file_object:
print(ln)
However, at this point the internal reference in the file_object have reached the end of the file, so if you wish to reuse the same object, you need to seek back to the beginning position, which is 0. As your assignment only states write to the file (and not on the screen), the above loop should be omitted from the file (but I get what you want to do, you want to see the contents of the file immediately though sometimes instructors are pretty strict on what they accept). Moving on:
count=1
file_input=open("numbered_lines.txt",'w')
for Line in file_object:
Looks pretty normal so far, again, minor formatting issues. In Python, typically we name all variables lower-case, as names with Capitalization are generally reserved for class names (if you wish to, you may read about them). Now we enter into the loop you got
print(count,' Line',(str))
This prints not quite what you want. as ' Line' is enclosed inside a quote, it is treated as a string literal - so it's treated literally as text and not code. Given that you had assigned Line, you want to take out the quotes. The (str) at the end simply just print out the string object and it definitely is not what you want. Also, you forgot to specify the file you want to print to. By default it will print to the screen, but you want to print it to the the numbered_lines.txt file which you had opened and assigned to file_input. We will correct this later.
count=+1
If you format this differently, you are assigning +1 to count. I am guessing you wanted to use the += operator to increment it. Remember this on your quiz/tests.
Finally:
file_object.close
file_input.close
They are meant to be called as functions, you need to invoke them by adding parentheses at the end with arguments, but as close takes no arguments, there will be nothing inside the parentheses. Putting everything together, the complete corrected code for your program should look like this
file_object = open("lines.txt", 'r')
count = 1
file_input = open("numbered_lines.txt", 'w')
for line in file_object:
print(count, line, file=file_input)
count += 1
file_object.close()
file_input.close()
Run the program. You will notice that there is an extra empty line between every line of text. This is because by default the print function adds a new line end character; the line you got from the file included a new-line character at the end (that's what make them lines, right?) so we don't have to add our own here. You can of course change it to an empty string. That line will look like this.
print(count, line, file=file_input, end='')
Naturally, other Python programmers will tell you that there are Pythonic ways, but you are just starting out, don't worry too much about them (although you can definitely pick up on this later and I highly encourage you to!)

The right way to open a file is using a with statement:
with open("lines.txt",'r') as file_object:
... # do something
That way, the context manager introduced by with will close your file at the end of "something " or in case of exception.
Of course, you can close the file yourself if you are not familiar with that. Not that close is a method: to call it you need parenthesis:
file_object.close()
See the chapter 7.2. Reading and Writing Files, in the official documentation.

In the first loop you're printing the contents of the input file. This means that the file contents have already been consumed when you get to the second loop. (Plus the assignment didn't ask you to print the file contents.)
In the second loop you're using print() instead of writing to a file. Try file_input.write(str(count) + " " + Line) (And file_input seems like a bad name for a file that you will be writing to.)
count=+1 sets count to +1, i.e. positive one. I think you meant count += 1 instead.
At the end of the program you're calling .close instead of .close(). The parentheses are important!

In place replacement of text in a file in Python

I am using the following code to upload a file on server using FTP after editing it:
import fileinput
file = open('example.php','rb+')
for line in fileinput.input('example.php'):
if 'Original' in line :
file.write( line.replace('Original', 'Replacement'))
file.close()
There is one thing, instead of replacing the text in its original place, the code adds the replaced text at the end and the text in original place is unchanged.
Also, instead of just the replaced text, it prints out the whole line. Could anyone please tell me how to resolve these two errors?

1) The code adds the replaced text at the end and the text in original place is unchanged.
You can't replace in the body of the file because you're opening it with the + signal. This way it'll append to the end of the file.
file = open('example.php','rb+')
But this only works if you want to append to the end of the document.
To bypass this you may use seek() to navigate to the specific line and replace it. Or create 2 files: an input_file and an output_file.
2) Also, instead of just the replaced text, it prints out the whole line.
It's because you're using:
file.write( line.replace('Original', 'Replacement'))
Free Code:
I've segregated into 2 files, an inputfile and an outputfile.
First it'll open the ifile and save all lines in a list called lines.
Second, it'll read all these lines, and if 'Original' is present, it'll replace it.
After replacement, it'll save into ofile.
ifile = 'example.php'
ofile = 'example_edited.php'
with open(ifile, 'rb') as f:
lines = f.readlines()
with open(ofile, 'wb') as g:
for line in lines:
if 'Original' in line:
g.write(line.replace('Original', 'Replacement'))
Then if you want to, you may os.remove() the non-edited file with:
More Info: Tutorials Point: Python Files I/O

The second error is how the replace() method works.
It returns the entire input string, with only the specified substring replaced. See example here.
To write to a specific place in the file, you should seek() to the right position first.
I think this issue has been asked before in several places, I would do a quick search of StackOverflow.
Maybe this would help?

Replacing stuff in a file only works well if original and replacement have the same size (in bytes) then you can do
with open('example.php','rb+') as f:
pos=f.tell()
line=f.readline()
if b'Original' in line:
f.seek(pos)
f.write(line.replace(b'Original',b'Replacement'))
(In this case b'Original' and b'Replacement' do not have the same size so your file will look funny after this)
Edit:
If original and replacement are not the same size, there are different possibilities like adding bytes to fill the hole or moving everything after the line.

python write method append

I'm stuck in a very basic problem of I/O in python. I'd like to insert some line in existing file (called ofe, output file), extracted from an source file (called ife, input file) according to arguments passed by user as stored in an list called lineRange (which has an index idx and values lineNumber).
This is the result:
for ifeidx,ifeline in enumerate(ife,1): #for each line of the input file...
with open(outFile,'r+') as ofe:
for idx,lineNumber in enumerate(lineRange,1): #... check if it's present in desired list of lines...
if (ifeidx == lineNumber): #...if found...
ofeidx = 0
for ofeidx, ofeline in enumerate(ofe,1):
if (ofeidx == idx): #...just scroll the the output file and find which is the exact position in desired list...
ofe.write(ifeline) #...put the desired line in correct order. !!! This is always appending at the end of out file!!!!
break
Problem is, the write() method is always pointing to the end of file, appending the lines instead of inserting them when scrolling the output file.
I really don't understand what's happening since the file is open in read+write (r+) mode, neither append (a) nor read+append (r+a) mode, .
I'm also aware that code will (should) overwrite the output file lines. Additional information are the OS WIndow7, Python version 2.7 and development tool is Eclipse with PyDev 3.7.1.xx
Any suggestion on what I'm doing wrong?

You can start by reading the whole file with readlines(), which will return a list. After that you just need to do list.insert(index, value) and write it again back to the file.
with open(outFile, "r") as f:
data = f.readlines()
data.insert(index, value)
with open(outFile, "w+") as f:
f.write(data)
Of course you should change this approach if you are dealing with a huge file.
By the way, if you are not using the with statement you should close the file in the end.

Reading in line from txt file in python

I'm having trouble it seems with reading in lines from a text file. When I do the whole f.readline() I can save it to a string and then print off the correct text however when lets say I go to print the first or second character of the string I just made it'll print a strange like dot checker pattern character instead of the correct letter.
Edit: Ok so when I try alfasin's method I seem to get the correct length of each line besides the first line that is read in. If I'm say reading in 5 lines and looking for a space, the first line with find the first space at spot 13 when it should find it at spot 8. However the next lines read in will all produce the correct length and location of the space.
Edit2: Also the text file I am reading in is UTF-8.
Edit3: Definitely was an issue with the encoding of the text file. I changed it to ANSI and everything started working as it should.

Try the following:
with open('filename.txt') as file:
for line in file:
print line
# and if you want to break it down to characters:
print list(line)

TypeError: expected a character buffer object - while trying to save integer to textfile

I'm trying to make a very simple 'counter' that is supposed to keep track of how many times my program has been executed.
First, I have a textfile that only includes one character: 0
Then I open the file, parse it as an int, add 1 to the value, and then try to return it to the textfile:
f = open('testfile.txt', 'r+')
x = f.read()
y = int(x) + 1
print(y)
f.write(y)
f.close()
I'd like to have y overwrite the value in the textfile, and then close it.
But all I get is TypeError: expected a character buffer object.
Edit:
Trying to parse y as a string:
f.write(str(y))
gives
IOError: [Errno 0] Error

Have you checked the docstring of write()? It says:
write(str) -> None. Write string str to file.
Note that due to buffering, flush() or close() may be needed before
the file on disk reflects the data written.
So you need to convert y to str first.
Also note that the string will be written at the current position which will be at the end of the file, because you'll already have read the old value. Use f.seek(0) to get to the beginning of the file.`
Edit: As for the IOError, this issue seems related. A cite from there:
For the modes where both read and writing (or appending) are allowed
(those which include a "+" sign), the stream should be flushed (fflush)
or repositioned (fseek, fsetpos, rewind) between either a reading
operation followed by a writing operation or a writing operation
followed by a reading operation.
So, I suggest you try f.seek(0) and maybe the problem goes away.

from __future__ import with_statement
with open('file.txt','r+') as f:
counter = str(int(f.read().strip())+1)
f.seek(0)
f.write(counter)

Just try the code below:
As I see you have inserted 'r+' or this command open the file in read mode so you are not able to write into it, so you have to open file in write mode 'w' if you want to overwrite
the file contents and write new data, otherwise you can append data to file by using 'a'
I hope this will help ;)
f = open('testfile.txt', 'w')# just put 'w' if you want to write to the file
x = f.readlines() #this command will read file lines
y = int(x)+1
print y
z = str(y) #making data as string to avoid buffer error
f.write(z)
f.close()