Different Way to Read in a File Python

In Python, there are a few ways you tin can read a text file.

In this article, I will go over the open() office, the read(), readline(), readlines(), close() methods, and the with keyword.

What is the open() function in Python?

If you lot want to read a text file in Python, yous first have to open it.

This is the basic syntax for Python's open() role:

                open("name of file you want opened", "optional mode")              

File names and right paths

If the text file and your current file are in the same directory ("folder"), and then you lot can simply reference the file name in the open() function.

                open up("demo.txt")              

Hither is an example of both files being in the same directory:

If your text file is in a unlike directory, then yous will need to reference the correct path name for the text file.

In this example, the random-text file is within a unlike folder and so main.py:

In order to admission that file in the main.py, you have to include the folder name with the name of the file.

                open("text-files/random-text.txt")              

If you lot don't have the correct path for the file, then you will become an error message similar this:

                open("random-text.txt")              

It is actually important to proceed track of which directory yous are in so you tin can reference the correct path name.

Optional Mode parameter in open()

In that location are different modes when you are working with files. The default way is the read mode.

The letter r stands for read fashion.

                open("demo.txt", mode="r")              

You tin can also omit mode= and just write "r".

                open("demo.txt", "r")              

There are other types of modes such as "w" for writing or "a" for appending.  I am not going to go into detail for the other modes because we are only going to focus on reading files.

For a complete list of the other modes, please read through the documentation.

Additional parameters for the open() function in Python

The open() function tin can have in these optional parameters.

• buffering
• encoding
• errors
• newline
• closefd
• opener

To acquire more than virtually these optional parameters, delight read through the documentation.

What is the readable() method in Python?

If you want to check if a file tin can be read, then you can use the readable() method. This volition return a True or False.

This example would return True because we are in the read way:

                file = open("demo.txt") print(file.readable())              

If I inverse this example, to "w" (write) mode, then the readable() method would render Faux:

                file = open("demo.txt", "w") print(file.readable())              

What is the read() method in Python?

The read() method is going to read all of the content of the file as i string. This is a skilful method to use if you don't have a lot of content in the text file.

In this example, I am using the read() method to print out a list of names from the demo.txt file:

                file = open("demo.txt") print(file.read())              

This method tin accept in an optional parameter chosen size. Instead of reading the whole file, only a portion of it volition be read.

If we change the earlier example, we tin print out merely the get-go word past calculation the number 4 as an argument for read().

                file = open("demo.txt") print(file.read(4))              

If the size argument is omitted, or if the number is negative, then the whole file volition be read.

What is the close() method in Python?

Once yous are done reading a file, it is important that you close it. If you forget to shut your file, then that tin crusade bug.

This is an example of how to close the demo.txt file:

                file = open up("demo.txt") print(file.read()) file.shut()              

How to employ the with keyword to close files in Python

One way to ensure that your file is closed is to use the with keyword. This is considered skillful practice, because the file will close automatically instead of you having to manually shut it.

Here is how to rewrite our example using the with keyword:

                with open("demo.txt") as file:     print(file.read())              

What is the readline() method in Python?

This method is going to read i line from the file and return that.

In this case, we accept a text file with these two sentences:

                This is the starting time line This is the second line              

If nosotros use the readline() method, it will merely print the kickoff sentence of the file.

                with open("demo.txt") as file:     impress(file.readline())              

This method likewise takes in the optional size parameter. We can modify the example to add together the number 7 to just read and impress out This is:

                with open up("demo.txt") as file:     impress(file.readline(7))              

What is the readlines() method in Python?

This method volition read and render a listing of all of the lines in the file.

In this example, we are going to print out our grocery items as a list using the readlines() method.

                with open("demo.txt") as file:     print(file.readlines())              

How to use a for loop to read lines from a file in Python

An alternative to these dissimilar read methods would exist to use a for loop.

In this case, we tin can print out all of the items in the demo.txt file past looping over the object.

                with open("demo.txt") every bit file:     for detail in file:         impress(item)              

Conclusion

If you want to read a text file in Python, you first have to open information technology.

                open("proper name of file you desire opened", "optional mode")                              

If the text file and your current file are in the aforementioned directory ("binder"), so y'all tin can just reference the file name in the open() function.

If your text file is in a different directory, then you will need to reference the correct path name for the text file.

The open() part takes in the optional mode parameter. The default mode is the read mode.

                open("demo.txt", "r")              

If you want to cheque if a file tin can be read, then you tin can utilize the readable() method. This will render a Truthful or False.

                file.readable()              

The read() method is going to read all of the content of the file equally one string.

                file.read()              

Once you are done reading a file, it is important that you close it. If y'all forget to shut your file, then that tin cause problems.

                file.close()              

1 mode to ensure that your file is airtight is to employ the with keyword.

                with open("demo.txt") as file:     print(file.read())              

The readline() method is going to read one line from the file and return that.

                file.readline()              

The readlines() method will read and return a list of all of the lines in the file.

                file.readlines()              

An alternative to these different read methods would be to use a for loop.

                with open("demo.txt") as file:     for item in file:         impress(item)              

I hope you enjoyed this commodity and best of luck on your Python journeying.

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