Python
Files handling
introduction.
when we need to write script or automate our work the first thing that came into our mind is that how we can deal with files to store our result or to read stored data.
so in this brief intro about how you can deal with files in python I hope this articale will help you
we will cover all things that you'll need to start working with files
Syntax.
first thing we need to know is the format or syntax to open files if exist in that specific path if not exist python will create an new one for you and dealing with it in python so in the following picture you will see the syntax then we will explain each part of it and all possible parameters that we can use.
now we can take each part of that syntax and see the need and possible values that can assigned to it
fileHandlerName : this is the name of the object that will contain all attributes(functions) that we will need to perform any operation on this file (eg. read , write , readlines ...)
open() : will open the specified file and return the handler object with specified mode.
file path : here we need some explain to this parameter which this always the path related to where is the terminal that you run this python so if you don't need to have a relative path then you need to specify the full path but we can do this with a lot of ways
let's explain some of these ways.
we can do this as we say "hard coded " so it will be never changed EX : "e:/Files_Test/test.c"
or we can path it to the terminal as argument :
but here we need to import sys library to use its attributes :
so we can use it like this : open ( sys.argv[1] , "r")
or if you need to use it as a parient path so you can use it as following : open (rf"{sys.argv[1]}/test.c")
or from importing os libarary
os.getcwd() : this will return current working directory
as you see a lot of ways to do the same thing this will add to you a lot of flexibility to development your script
now with the last parameter we have here a lot of selectable choices this will be depending on your need
now we can make a full example of how to open specific file with python
now after we successfully opining the file we need to now about the attached attributes(functions) with the file object handler
File reading methods
Read whole file
read current cursor line
read all lines
we can control the position of the cursor using FileHandlerName.seek(0 , 0 ) so we can navigate in file using this method ]
seek take two arguments ( Offset , Position )
Offset : the position of where the cursor in the line
Position : take 3 values ( 0 : file beginning , 1 : current line , 2 : end of file )
File Writing methods
Write string
write lines
now we learnt the basics of how to( open , read and write ) data into specific file
so if you need some advanced information about python with files you can take a look on the following some commands such ( copy , move , delete , rename )
but these commands need some methods from os library
to delete file : os.remove("FilePath")
to reanme file : os.rename("OldName" , "NewName")
to move file : move files we need to import "shutil" library and use move( source , Dist.) function or with os library we can use os.rename with the same parameters
to copy file from location to another location we all from shutil library we can use copy function with the same parameters as move() function or we can create a new file in required location and copy the content from the source into destination
to list all content in specific directory you can use this method os.listdir("then the directory ")