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Python File

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Like any other programming language, Python does support File handing. I mean, Python provides various functions that allows us to create a file, open file, read the data and write data to a file. Unlike other languages, Python handle files differently. Python treats Files as text or binary based on the data, and each line has to terminate with an End Of Line characters like newline, comma etc.

Python provides an important function called open() to work with files. The Python File open function accepts two parameters, and they are file_name and mode.

The basic syntax behind this Python file open function is as shown below

f_open = open(“File_Name”, “mode”)

The mode argues an optional argument. There are four different modes in Python for opening a file.

  • r – It means, Read Mode, and this is the default mode of Python file open. This will open an existing file for reading, if there is no file than it throws an error.
  • r+ – This is for both reading and writing mode.
  • a – Means Append. If the file exists then this opens that file and append the data to the existing content. If there is no file then it creates a new file with the name we specified.
  • w – Means Write mode. It opens a file in write mode, and overrides the existing content with new content. It create a new file, if the file doesn’t exist.
  • x – Use this to create a new file. This throws an error, if the file exists.
  • Apart from these modes, you can also specify the type of data that the file has to handle. I means, binary data or text mode
  • t – Text Mode and this is the default mode.
  • b – Binary mode 
f_open = open("PythonSample.txt")

The above code is equal to f_open = open(“PythonSample.txt”, “rt”)

Python File Operations

The following list of examples helps you to Create a New File in Python, Open, Rename it, Delete, Write text to a File, File close, append, write, read options that are available in Python.

To demonstrate most of these function, we used the following text file

Python File Examples

Python Open File

In Python, you can open a file either specifying the file name or the full path. Full name will open the file in current working Directory however, using fullpath, you can access files at any directory. Before we start, let me use listdir function to get the files list in the current directory. 

import os

print(os.getcwd())
print(' ')
print(os.listdir())

OUTPUT

Python File Open

In Python, you can open a file either specifying the file name or the full path. 

f_open = open("PythonSample.txt")

Or  use full path

f_open = open("C:/users/Document/PythonSample.txt")

Python read file

The Python read function is used to read the data inside a file. This is a simple File example, which will open a sample text file in read mode. Next, we used the read function to read data inside that text file.

f_open = open("PythonSample.txt", "r")
print(f_open.read())

OUTPUT

Python Read File

While working with string data, you can use the read function with parameter to restrict the number of characters returned by the read function. For example, read(5) reads first five characters or read(10) read first 10 characters.

f_open = open("PythonSample.txt", "r")
print(f_open.read(5))
print(f_open.read(2))

OUTPUT

Python Read File 1

As you can see from the above screenshot, first read statement prints first five characters. Next, read is printing the next two. If you want to print the first 10 then you have to close and reopen the file.

f_open = open("PythonSample.txt", "r")
print(f_open.read(5))

f_open = open("PythonSample.txt", "r")
print(f_open.read(8))

OUTPUT

Python Read File 2

Read file using For Loop

You can also use loops to read all the data in a sequence. For instance, the below example uses For Loop to read each and every line available in this text file.

f_open = open("PythonSample.txt", "r")
for char in f_open:
    print(char)

OUTPUT

Python Read File 3

This example loop over the complete file in the sample text file and prints each and every line.

f_open = open("PythonSample.txt", "r")
for line in f_open:
    print(line, end = '')

OUTPUT

Python Read File 4

Python readline function

The Python readline function reads the complete line before the end of line character. This example opens a file and reads first line from it.

f_sample = open("PythonSample.txt", "r")
print(f_sample.readline())

OUTPUT

Python readline function 1

If you want to read two lines then call readline function twice and so on. Let me print three lines

f_sample = open("PythonSample.txt", "r")
print(f_sample.readline())
print(f_sample.readline())
print(f_sample.readline())

OUTPUT

Python readline function 2

You can use this readline function to read or print the required line also. Below code prints 2nd line from the text file.

If you use the readline function along with an argument then this will behave same as read function with parameter. I mean, readline(2) = read(2)

f_sample = open("PythonSample.txt", "r")
print(f_sample.readline(2))
print()
 
f_sample = open("PythonSample.txt", "r")
print(f_sample.read(2))

OUTPUT

Python readline function 3

Python readlines function

In Python, we have one more function called readlines(). This will reads data from the given text file, and prints all the data in a list format. This will separate each and every line with a proper separator.

f_sample = open("PythonSample.txt", "r")
print(f_sample.readlines())

OUTPUT

Python readlines function

Python file close function

As the name suggest, it will close an already opened file. Although, Python has a Garbage Collector to close the files you should not rely completely on this. It is always a good practice to close the opened file.

Here, we opened a file, read a single line and then closed that file.

f_sample = open("PythonSample.txt", "r")
print(f_sample.readline())
f_sample.close()

OUTPUT

Python file close function 1

Let me print another line from that closed file. 

f_sample = open("PythonSample.txt", "r")
print(f_sample.readline())

f_sample.close()
print(f_sample.readline())

OUTPUT

Python file close function 2

You can notice the error thrown by Python shell. I am sure, you can read and understand the message.

The above program show you the use of close method. However, it is not advisable to use the way that we shown above. In real-time, you have to use with statement to properly close the opened files. Or, some people say, we can go with try finally block. We show you both

Python File using Try finally

try:
    f_sample = open("PythonSample.txt", "r")
    print(f_sample.read())
finally:
    f_sample.close()

OUTPUT

Python file Try Finally

Python with Statement

The Python with statement make sure that every file opened by this will be closed irrespective of the errors. Here, we used with statement 

with open("PythonSample.txt", "r") as f_sample:
    print(f_sample.read())
f_sample.close()

OUTPUT

Python With File 1

Python with statement is not about closing the file. You can use this with statement to open a file any mode. I mean, you can use this to read data, write data so on. Most importantly, we use this in case of file manipulations where we have to execute multiple statements. This statement holds them in a block so, we can write multiple statements in that block.

with open("PythonSample.txt", "w") as f_sample:
    f_sample.write("First Line")
    f_sample.close()
 
with open("PythonSample.txt", "r") as f_sample:
    print(f_sample.read())
f_sample.close()

OUTPUT

Python With File 2

Python File Write

Python provides write function to write a content or data to a file. 

Before we get into the example, I assume you remember what I said earlier. You have to use either a mode for append or w for write mode.

This example opens the Sample text in write mode and write a welcome message. Next, we opened that file to print the data.

f_demo = open("PythonSample.txt", "w")
f_demo. write("Welcome to Tutorial gateway")
f_demo.close()
 
# Let me open the file and check
f_demo = open("PythonSample.txt", "r")
print(f_demo.read())

OUTPUT

Python File Write 1

This time, we will write multiple lines of code using the write function.

f_writedemo = open("PythonSample.txt", "w")
f_writedemo. write("Python")
f_writedemo. write("\nTutorial gateway")
f_writedemo. write("\nHappy Coding!")
f_writedemo. write("\nHi \nHello \nCheers")
f_writedemo.close()
 
# Let me open the file and check
f_writedemo = open("PythonSample.txt", "r")
print(f_writedemo.read())

OUTPUT

Python File Write 2

We have been working on this file from the beginning, and you know the data. However, this write function erased everything and returned this Welcome message.

Python provides writelines function to write data to files. This function accepts list as an argument so, you can write a list off items at one go. I mean, without using multiple write functions.

f_writelinesdemo = open("PythonSample.txt", "w")
text = ["First Line\n", "Second Line\n", "Third Line\n", "Fourth Line"]
f_writelinesdemo. writelines(text)
f_writelinesdemo.close()
 
# Let me open the file and check
f_writelinesdemo = open("PythonSample.txt", "r")
print(f_writelinesdemo.read())

OUTPUT

Python File Write 3

Python File append

This time, we are opening a file in append mode, and check what will happen after writing a hello message

f_demo = open("PythonSample.txt", "a")
f_demo. write("\nHell World!")
f_demo.close()
 
# Let me open the file and check
f_demo = open("PythonSample.txt", "r")
print(f_demo.read())

OUTPUT

Python File Append

Write to a File using Loop

You can also use the for loop to write multiple lines of information. Here, we are sampling writing 10 lines in a Sample10 text file.

f_loopdemo = open("Sample10.txt", "w")
for i in range(1, 11):
    f_loopdemo.write("This is the %d Line\n" %(i))
f_loopdemo.close()
 
# Let me open the file and check
f_loopdemo = open("Sample10.txt", "r")
print(f_loopdemo.read())

OUTPUT

Python File Write using For Loop

Create a New File in Python

Until now, we are working with the existing files. However, you can create your own file using the read method. For this you have to use either x for creating a new file, a mode or w mode. All theses three modes with create a new file but the last two modes different

f_create = open("NewFile.txt", "x")

Let me create another file in Python and write something to it. So that you can see the New file along with text. This program creates Sample1 text file and writes Python Program string and closes it. Next, we opened that file in read mode and printing the data from it.

f_create = open("Sample1.txt", "x")
f_create.write("Python Program")
f_create.close()
 
# Open the Sample1 file
f_create = open("Sample1.txt", "r")
print(f_create.read())

OUTPUT

Python File Create 1

This example uses the w for write mode to create a new files and writes something to it.

f_wcreate = open("Sample2.txt", "x")
f_wcreate.write("Python Tutorial")
f_wcreate.close()
 
# Open the Sample1 file
f_wcreate = open("Sample2.txt", "r")
print(f_wcreate.read())

OUTPUT

Python File Create 2

This time we are suing the open function along with a mode – append mode.

f_acreate = open("Sample3.txt", "x")
f_acreate.write("Tutorial Gateway")
f_acreate.close()
 
# Open the Sample1 file
f_acreate = open("Sample3.txt", "r")
print(f_acreate.read())

OUTPUT

Python File Create append mode

Rename a File in Python

In order to rename a file within a directory, you have to import the os module. Within the os module, we have a rename function that helps us to rename an existing files in a directory.

Let me use this Python file rename function to rename Sample2.txt file to NewSample.txt. Next, we opened that renamed file to see the data inside that file.

import os
os.rename("Sample2.txt", "NewSample.txt")
 
f_sample = open("NewSample.txt", "r")
print(f_sample.read())

OUTPUT

Python File Rename

Delete a File in Python

In order to delete a Python file from a directory, you have to import the os module. Within the os module, we have a remove function that helps us to remove files from a directory.

Let me use this Python file remove function to delete Sample3.txt file that we created before.

import os
os.remove("Sample3.txt")

OUTPUT

Python File Delete 1

It works like a charm however, if you try to delete a file that doesn’t exist with throw an error. Let me remove the Sample3.txt that we deleted before.

You can see from the above, it is throwing and error: FileNotFoundError: [Errno 2] No such file or directory: ‘Sample3.txt’

To avoid this situation, it is advisable to check whether the file exist or not.

import os
if os.path.exists("Sample3.txt"):
    os.remove("Sample3.txt")
else:
    print("Hey! No such file exists")

OUTPUT

Python Delete File 2

Python seek and tell Functions

Python provides two functions to find the pointer position in a file. 

  • tell(): It tells you the current pointer position. 
  • seek(): To set the pointer position to specific position. 
with open("PythonSample.txt", "r") as f_sample:
    print("File Pointer Initial Position : ", f_sample.tell())
    print(f_sample.read())
    print("Current File Pointer Position : ", f_sample.tell())
     
    f_sample.seek(22)
    print("\nCurrent File Pointer Position : ", f_sample.tell())
 
f_sample.close()

OUTPUT

Python File seek

Python File Attributes

Python provides the following attributes to get the information about the file that you are working with.

  • file.name: This returns the name of the file.
  • file.mode: On what mode you opened this file. For example, r mode, w mode etc
  • File.closed: returns True if the given file is closed otherwise, False. 
f_open = open("PythonSample.txt", "r")
print(f_open.read())

print('\nFile Name = ', f_open.name)
print('File Mode = ', f_open.mode)
print('File closed? = ', f_open.closed)

f_open.close()
print('\nFile closed? = ', f_open.closed)

OUTPUT

Python File Attributes