python file open

Open a File on the Server

Assume we have the following file, located in the same folder as Python:

demofile.txt



Hello! Welcome to demofile.txtThis file is for testing purposes.Good

Luck!

demofile.txt

To open the file, use the built-in open() function.

The open() function returns a file object, which has a

read() method for reading the content of the file:

Example



f = open("demofile.txt", "r")print(f.read())

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Example

If the file is located in a different location, you will have to specify the file path,

like this:

Example

Open a file on a different location:



f = open("D:\\myfiles\welcome.txt", "r")print(f.read())

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Example

Open a file on a different location:

Read Only Parts of the File

By default the read() method returns the whole text, but you can also specify how many characters you want to return:

Example

Return the 5 first characters of the file:



f = open("demofile.txt", "r")print(f.read(5))

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Example

Return the 5 first characters of the file:

Read Lines

You can return one line by using the readline() method:

Example

Read one line of the file:



f = open("demofile.txt", "r")print(f.readline())

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Example

Read one line of the file:

By calling readline() two times, you can read the

two first lines:

Example

Read two lines of the file:



f = open("demofile.txt", "r")print(f.readline())print(f.readline())

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Example

Read two lines of the file:

By looping through the lines of the file, you can read the whole file, line by line:

Example

Loop through the file line by line:



f = open("demofile.txt", "r")for x in f:  print(x)

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Example

Loop through the file line by line:

Close Files

It is a good practice to always close the file when you are done with it.

Example

Close the file when you are finish with it:



f = open("demofile.txt", "r")print(f.readline())

f.close()

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Example

Close the file when you are finish with it:

Note: You should always close your files, in some cases, due to buffering, changes made to a file may not show until you close the file.