Working with files in Python

Some notes about working with files in Python.

How simply generate path:

import os
os.path.join('usr', 'user', 'Documents')

or if we need path to file:

os.path.join('home/Documents/work', important.txt)

os.getcwd() - check current directory

os.chdir('path to new working directory') - change directory

os.makedirs('home/docs/test') - create directory

os.path.abspath('path') - get absolute path

os.path.relpath('path', 'start point') - get relative path

os.path.dirname('path') - get directory name actually will return name with whole path

os.path.basename('path') - get file name

os.path.split('path') - to get both directory name and file name as a tuple

or 

examplePath.split(os.path.sep) - will return tuple where every directory and file name are separate strings (in OSX first item in the list will be '')

os.path.listdir('path') - list all items in the directory

os.path.getsize('path') - get file size in bytes

os.path.exists('path') - returns True if directory or file exists

os.path.isfile('path') - returns True if file exists

os.path.isdir('path') - returns True if directory exists

open('path') - returns file object if there's no such file Python will create that

read('path') or open('path', 'r')- reads file

file.readlines() - reads line by line from file

write('path') or open('path', 'w')- writes to file (simple usage will overwrite all content)

open('path', 'a') - will append text to the end of the file instead of overwriting

close('path') - closes file


Work with binary shelf files (can be used as dictionaries etc.):

import shelve
testFile = shelve.open('filename')
testValues = ['email', 'address', 'phone']
testFile['data'] = testValues
testFile.close()

testFile('data') - prints out values

list(testFile.keys()) - prints list of keys in our case it will be just 'data'

list(testFile.values()) - prints list of values ie ['email', 'address', 'phone']

import pprint
pprint.pformat(list) - will represent list / dictionary as a string for easier saving that to a file

And for the end short reminder about shelf files and plain text files: first used mostly for complex objects (ie file objects) while plain text files can be used for storing simple data (ie text, integers etc)