Python is the best coding language for beginners – easy to pick up and implement. The vast number of frameworks and libraries that come with python is impressive and especially useful in machine learning and data analytics. Python is also an interpreted language rather than compiled, which allows easy identification of runtime error sources. The considerable flexibility that python offers users is genuinely one of a kind.
Today’s article will demonstrate the use of the ‘with open’ statement in python.
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Python “open” Statement
The ‘with open‘ is technically an extension of the ‘open‘ statement, both used for file handling in a python environment. File handling is the creation, deletion, and storage of files, with updating and editing as per requirement in between.
To work with a file within python, opening it is the first step. And that is precisely what the open statement does- it opens the file.
For instance, let’s say we have a text file saved under the name ‘hello.txt‘ and we have the following lines of text in it:
Good morning everyone.
Hope everyone has a good day ahead.
To open it in python, we are first required to declare a variable for the function. For example, ‘my_file‘. This variable will allow us to access the file and call different functions upon it as and when required.
Parameters In “open” Statement
The open statement takes several parameters, but the most important is the filename, which we have provided as ‘hello.txt‘, and the mode, which we have provided as ‘r‘. The other parameters are optional. For example:
- ‘Encoding‘, used to specify the encoding, and
- ‘Buffering‘, used to set the buffering policy.
The above parameters are optional, and we do not require to specify these for the functioning of the open statement.
Modes In “open” Statement
There are quite a few modes:
- ‘r‘ or ‘read‘ mode being the default one.
- ‘w‘ or the ‘write‘ mode for entirely overwriting text documents.
- ‘x‘ for exclusive creation and opening of a file.
- ‘a‘ for appending into a file.
- ‘b‘ for specifically opening a binary file, and so on.
Python Syntax For Reading and Closing A File
After opening a file, we pass a print function “to read” and output the file content.
After we’re done opening and reading our file content, we need to close it. Closing a file is particularly mandatory, as failure to do so can result in loss of data and corrupted files.
Now that our file is closed and safe, here is the output:
[“Good morning everyone.
Hope everyone has a good day ahead”].
Similarly, if we want to ‘write‘ or overwrite the file, our code will look like this:
my_file= “open(‘hello.txt’,’ w’)
my_file.write(“Yes, we are good”)
The ‘readlines‘ function returns the file’s content as string elements of a list.
So the output will be:
[‘Yes, we are good’]
Python “with open” Statement
Now coming to our subject for the day, the ‘with open‘ statement functions the same as the ‘open’ function. The difference is that, unlike the open statement, we don’t have to close the file explicitly with this function. This allows for hassle-free code writing, making the code look cleaner and much more compact.
It might not be apparent with just three lines of code, as illustrated here, but when programmers have to deal with thousands of lines of code, it is common to forget about closing the hundreds of files after opening them. Thus, the ‘with open’ statement is a much better practice.
The parameters of the ‘with open’ function remain the same as the’ open’ function. Filename and mode are the only two that we use here.
To carry on with the example, if we want to read the file as before, the syntax will be:
my_file = with open(‘hello.txt’,’r’)
And that is it. We don’t have to add another line of code to close the file. The output would be:
[“Yes, we are good”].
(Remember we overwrote the initial file)
To overwrite again, this time using the ‘with open‘ statement,
my_file.write(“Can we meet for coffee”,” Tell me a good time”)
As expected, we will get an output as string elements of a list:
[“Can we meet for coffee”,” Tell me a good time”]
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So, this is how a very basic ‘with open’ statement functions in python. The optional parameters can be specified and experimented with, to fine-tune the function per our needs further.