Python Read First 5 Lines of File

In Python, at that place are a few ways you tin can read a text file.

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

What is the open() function in Python?

If you want to read a text file in Python, you first take to open it.

This is the basic syntax for Python'southward open() part:

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

File names and correct paths

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

                open("demo.txt")              

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

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

In this example, the random-text file is inside a different folder and then master.py:

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

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

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

                open("random-text.txt")              

It is really important to proceed runway of which directory you are in so you can reference the correct path name.

Optional Mode parameter in open()

There are different modes when yous are working with files. The default mode is the read mode.

The letter r stands for read fashion.

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

You can also omit fashion= and simply write "r".

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

In that location are other types of modes such equally "west" for writing or "a" for appending.  I am not going to go into item for the other modes because we are just going to focus on reading files.

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

Additional parameters for the open up() function in Python

The open up() function can take in these optional parameters.

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

To larn more than most these optional parameters, please read through the documentation.

What is the readable() method in Python?

If you want to check if a file can be read, then y'all can apply the readable() method. This will return a True or Fake.

This example would return True considering we are in the read mode:

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

If I changed this example, to "w" (write) way, then the readable() method would return False:

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

What is the read() method in Python?

The read() method is going to read all of the content of the file as 1 string. This is a good method to utilise if yous don't take a lot of content in the text file.

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

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

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

If nosotros alter the earlier example, we can print out only the first word by adding 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 will be read.

What is the shut() method in Python?

Once you are done reading a file, information technology is important that yous close it. If y'all forget to close your file, and then that can cause issues.

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

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

How to use the with keyword to shut files in Python

One way to ensure that your file is airtight is to apply the with keyword. This is considered good practise, because the file will close automatically instead of you having to manually close it.

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

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

What is the readline() method in Python?

This method is going to read 1 line from the file and return that.

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

                This is the first line This is the second line              

If we apply the readline() method, it will only print the first sentence of the file.

                with open up("demo.txt") every bit file:     print(file.readline())              

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

                with open("demo.txt") every bit file:     print(file.readline(7))              

What is the readlines() method in Python?

This method will read and render a list 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") every bit file:     print(file.readlines())              

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

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

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

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

Determination

If you want to read a text file in Python, you commencement have to open it.

                open up("name of file y'all want opened", "optional mode")                              

If the text file and your current file are in the aforementioned directory ("binder"), then you can just reference the file proper noun in the open() function.

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

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

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

If you want to check if a file can exist read, then you can use the readable() method. This will return a True or Fake.

                file.readable()              

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

                file.read()              

Once you are done reading a file, it is important that you lot close it. If you forget to close your file, so that can cause problems.

                file.shut()              

One way to ensure that your file is airtight is to use the with keyword.

                with open("demo.txt") equally file:     impress(file.read())              

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

                file.readline()              

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

                file.readlines()              

An alternative to these dissimilar read methods would be to utilize a for loop.

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

I hope you enjoyed this article and all-time of luck on your Python journeying.

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