In Python, there is no need for importing external library to read and write files. Python provides an inbuilt function for creating, writing and reading files.
In this tutorial, we will learn:
With Python you can create a .text files (guru99.txt) by using the code, we have demonstrated here how you can do this
Step 1)
f= open("guru99.txt","w+")
Step 2)
for i in range(10):
f.write("This is line %d\r\n" % (i+1))
Step 3)
f.close()
Here is the result after code execution
When you click on your text file in our case “guru99.txt” it will look something like this
You can also append a new text to the already existing file or the new file.
Step 1)
f=open("guru99.txt", "a+")
Once again if you could see a plus sign in the code, it indicates that it will create a new file if it does not exist. But in our case we already have the file, so we are not required to create a new file.
Step 2)
for i in range(2):
f.write("Appended line %d\r\n" % (i+1))
This will write data into the file in append mode.
You can see the output in “guru99.txt” file. The output of the code is that earlier file is appended with new data.
Not only you can create .txt file from Python but you can also call .txt file in a "read mode"®.
Step 1) Open the file in Read mode
f=open("guru99.txt", "r")
Step 2) We use the mode function in the code to check that the file is in open mode. If yes, we proceed ahead
if f.mode == 'r':
Step 3) Use f.read to read file data and store it in variable content
contents =f.read()
Step 4) print contents
Here is the output
You can also read your .txt file line by line if your data is too big to read. This code will segregate your data in easy to ready mode
When you run the code (f1=f.readlines()) for reading the file or document line by line, it will separate each line and present the file in a readable format. In our case the line is short and readable, the output will look similar to the read mode. But if there is a complex data file which is not readable, this piece of code could be useful.
Here is the complete code
Python 2 Example
def main():
f= open("guru99.txt","w+")
#f=open("guru99.txt","a+")
for i in range(10):
f.write("This is line %d\r\n" % (i+1))
f.close()
#Open the file back and read the contents
#f=open("guru99.txt", "r")
# if f.mode == 'r':
# contents =f.read()
# print contents
#or, readlines reads the individual line into a list
#fl =f.readlines()
#for x in fl:
#print x
if __name__== "__main__":
main()
Python 3 Example
def main():
f= open("guru99.txt","w+")
#f=open("guru99.txt","a+")
for i in range(10):
f.write("This is line %d\r\n" % (i+1))
f.close()
#Open the file back and read the contents
#f=open("guru99.txt", "r")
#if f.mode == 'r':
# contents =f.read()
# print (contents)
#or, readlines reads the individual line into a list
#fl =f.readlines()
#for x in fl:
#print(x)
if __name__== "__main__":
main()
Summary
Python File Handling | File Operations in Python | Learn python programming
This Edureka live session on File Handling with Python covers all the important aspects of using files in Python right from the introduction to what fields are, all the way till checking out the major aspects of working with files and using the code-first approach to understand them better.
#python #web-development