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.txt
This file is for testing purposes.
Good
Luck!
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:
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")
print(f.read())
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Using the with statement
You can also use the with statement when opening a file:
Then you do not have to worry about closing your files, the with statement takes care of that.
Close Files
It is a good practice to always close the file when you are done with it.
If you are not using the with statement, you must write a close statement in order to close the file:
Example
Close the file when you are finished with it:
f = open("demofile.txt")
print(f.readline())
f.close()
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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.
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:
with open("demofile.txt") as f:
print(f.read(5))
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Read Lines
You can return one line by using the readline() method:
Example
Read one line of the file:
with open("demofile.txt") as f:
print(f.readline())
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By calling readline() two times, you can read the
two first lines:
Example
Read two lines of the file:
with open("demofile.txt") as f:
print(f.readline())
print(f.readline())
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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:
with open("demofile.txt") as f:
for x in f:
print(x)
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