How to open a file in python
Open a File on the ServerAssume we have the following file, located in the same folder as Python: Show
demofile.txt Hello! Welcome to demofile.txt To open the file, use the built-in The Example f = open("demofile.txt",
"r") Run Example » If the file is located in a different location, you will have to specify the file path, like this: ExampleOpen a file on a different location: f = open("D:\\myfiles\welcome.txt", "r") Run Example » Read Only Parts of the FileBy default the ExampleReturn the 5 first characters of the file: f = open("demofile.txt", "r") Run Example » Read LinesYou can
return one line by using the ExampleRead one line of the file: f = open("demofile.txt", "r") Run Example » By calling ExampleRead two lines of the file: f = open("demofile.txt",
"r") Run Example » By looping through the lines of the file, you can read the whole file, line by line: ExampleLoop through the file line by line: f = open("demofile.txt", "r") Run Example » Close FilesIt is a good practice to always close the file when you are done with it. ExampleClose the file when you are finish with it: f = open("demofile.txt", "r") Run Example » 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. Files are named locations on disk to store related information. They are used to permanently store data in a non-volatile memory (e.g. hard disk). Since Random Access Memory (RAM) is volatile (which loses its data when the computer is turned off), we use files for future use of the data by permanently storing them. When we want to read from or write to a file, we need to open it first. When we are done, it needs to be closed so that the resources that are tied with the file are freed. Hence, in Python, a file operation takes place in the following order:
Opening Files in PythonPython has a built-in
We can specify the mode while opening a file. In mode, we specify whether we want to
read The default is reading in text mode. In this mode, we get strings when reading from the file. On the other hand, binary mode returns bytes and this is the mode to be used when dealing with non-text files like images or executable files.
Unlike other languages, the character Moreover, the default encoding is platform dependent. In windows, it is So, we must not also rely on the default encoding or else our code will behave differently in different platforms. Hence, when working with files in text mode, it is highly recommended to specify the encoding type.
Closing Files in PythonWhen we are done with performing operations on the file, we need to properly close the file. Closing a file will free up the resources that were tied with the file. It is done using the Python has a garbage collector to clean up unreferenced objects but we must not rely on it to close the file.
This method is not entirely safe. If an exception occurs when we are performing some operation with the file, the code exits without closing the file. A safer way is to use a try...finally block.
This way, we are guaranteeing that the file is properly closed even if an exception is raised that causes program flow to stop. The best way to close a file is by using the We don't need to explicitly call the
Writing to Files in PythonIn order to write into a file in Python, we need to open it in write We need to be careful with the Writing a
string or sequence of bytes (for binary files) is done using the
This program will create a new file named We must include the newline characters ourselves to distinguish the different lines. Reading Files in PythonTo read a file in Python, we must open the file in reading
There are various methods available for this purpose. We can use the We can read the
We can see that the We can change our current file cursor (position) using the
We can read a file line-by-line using a for loop. This is both efficient and fast.
In this program, the lines in the file itself include a newline character Alternatively, we can use the
Lastly, the
Python File MethodsThere are various methods available with the file object. Some of them have been used in the above examples. Here is the complete list of methods in text mode with a brief description:
How do I make a file open in Python?We can create a file using the built-in function open() . Pass the file name and access mode to the open() function to create a file.
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Create A Empty Text File.. How do I open a text file in Python?To read a text file in Python, you follow these steps: First, open a text file for reading by using the open() function. Second, read text from the text file using the file read() , readline() , or readlines() method of the file object.
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1) open() function.. How do I open and read a file in Python?There are 6 access modes in python.. Read Only ('r') : Open text file for reading. ... . Read and Write ('r+'): Open the file for reading and writing. ... . Write Only ('w') : Open the file for writing. ... . Write and Read ('w+') : Open the file for reading and writing. ... . Append Only ('a'): Open the file for writing.. How do I open a .out file in Python?To open the file, use the built-in open() function.
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