Explains How To Read And Write A File Using Javascript

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The open () function opens a file. You must use "r" mode to read a file. The read (), readline (), readlines () functions return the contents of an open file.

Python is a useful programming language to use if you want to process data. The language has several built-in functions that make it easier to read, write, and manipulate data or files.

Suppose you have a list of employee names and you want to check if a user’s name is there. You can save the list of employee names as a file. Then you can use Python to read this file and check if the employee name is stored in this file.

In this tutorial, we’ll explore the basics of reading files in Python. To get started, we’ll discuss how to open and access a file. We will therefore explore how to read a file in Python.

Open a file to read it in Python

The first step in reading a file in Python is to open the file you want to read. You need to tell Python the name of the file you want to open.

To read a file, you must first tell Python where that file is located. You can do this by specifying the path to the file and declaring it in a variable.

Here is the syntax for opening a file in Python:

Our code opens a file in the path we defined in the variable " filename " .

The r at the end of the open ( ) tells Python that we just want to read our file. We could change this flag if we wanted to modify our file.

Python read file

Now that our file is open, we can read it through Python. There are three functions we can use to read data from a file, which are as follows:

Let’s detail how each one works. read () can return the entire contents of a file as a string.

Python Read Text File

Here is an example of read () by operating on a text file which contains a list of names:

Our program returns the following:

The read () returned everything in our names file, including the newline characters at the end of our string.

The readline () function returns the following line to a file. readline () returns the text and newline character at the end of the file. The following code will read the first line of our file:

Our code returns:

If we wanted to read the first and second lines of our existing file, we had to use the readline () function again:

Our code returns the following output:

Python Read file line by line

The readline () function can be useful if you want to read a file line by line. The function is commonly used in a for loop to read multiple lines from a file, like this:

Our code returns the following:

Finally, the readlines () method returns a list of lines in a file. This function returns an array and each element represents a single line in a file:

The program returns the following:

Once you have read a file, you cannot replay it. Then, when you have read the file using readlines (), trying to replay the file using any read file operation will return an empty string. If you want to read a file more than once, you will have to reopen it and read it.

Conclusion

You can use read (), readline ( ) and readlines () functions to read parts of a file. Then you manipulate the data as needed. Today we covered how to open a file, read it using specific methods, and how to close it in Python.

You are now ready to open and read Python files like an expert ! To learn more about Python, read our guide on How to Code Python .

👻 Read also: what is the best laptop for engineering students?

We hope this article has helped you to resolve the problem. Apart from Explains How To Read And Write A File Using Javascript, check other array Python module-related topics.

Want to excel in Python? See our review of the best Python online courses 2023. If you are interested in Data Science, check also how to learn programming in R.

By the way, this material is also available in other languages:



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