python how to check if file exists or not / directory exists or not

we know than python is the most exposing programming language in the artificial intelligence world ,so many of the using python as the primary programming language for building their applications,in some application we may come across a situation to check whether the file exists or directory exists using python. so in this section let see in python how to check if file exists or not / directory exists or not, fortunately we have python OS library function to check if file exists or not / directory exists or not. os.path.isdir is used in python to check if directory exists and os.path.exists() is used in python to check if file exists or not.

Lets See the Syntax
1) os.path.isdir() it return True or False based on if directory exists or not

#pythontest.py

import os 
print(os.path.isdir("D:/testvs"))    // Already one directory exists
print(os.path.isdir("D:/testvs2020"))  // directory not exists

OUT PUT

True
False



In python how to check if file exists or directory exists

2) os.path.exists() it return True or False based on if file exists or not

#pythontest.py

import os
print(os.path.exists("D:/testvs2020/pythontest.py"))
print(os.path.exists("D:/testvs/pythontest.py"))

OUT PUT

False
True


In python how to check if file exists or not

How to create a small project using Django

In the last tutorial we learned how to install a Django so in this section we are going to discuss how to create a small project using Django. we already created Django admin users using the Django manage.py createsuperuser .In this “create a small project using Django” tutorial we are going to create a small blog that allow users to post their thoughts one by one lets see in detail

Steps to create a small project using Django

1) Create your app first

#python manage.py startapp tutorialshore

How to create a small project using Django step 1

See the automatically created folder structure

How to create a small project using Django step 1 project structure

__init__.py : package files
admin.py : This files is help to make the changes in the admin interface
models.py : This is one of the important files all the application are stored in this files
tests.py : Create your tests here.
views.py : This is another important files all the views interface managed by this files

 

2) We have to change URL pattern open myblog =>myblog=>urls.py

Add below code

from django.urls import include
from django.urls import path
urlpatterns += [
    path('tutorialshore/', include('tutorialshore.urls')),
]

Then urls.py become

"""myblog URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path

urlpatterns = [
    path('admin/', admin.site.urls),
	
]
from django.urls import include
from django.urls import path
urlpatterns += [
    path('tutorialshore/', include('tutorialshore.urls')),
]

3) Create a new urls.py file inside tutorialshore folder and add below lines

 

from django.urls import path
from . import views

urlpatterns = [
    path('', views.index, name='index'),
    path('post/', views.post, name='post'),
  
]

4)  Open view.py files add below code

 

from django.shortcuts import render
from django.http import HttpResponse

def post(request):
 text = """<h1>welcome to my post View !</h1>"""
 return HttpResponse(text)
 
def index(request):
 text = """<h1>welcome to my blog!</h1>"""
 return HttpResponse(text)

# Create your views here.



5) Run # python manage.py runserver

5) Open http://127.0.0.1:8000/tutorialshore/ in your browser

 

How to create a small project using Django step 2

6) open http://127.0.0.1:8000/tutorialshore/post/

How to create a small project using Django step 3

Next => How to create new admin user or super user in Django python

python f string or python Formatted string literals

python f string is a new string formatting method in python, f string is much simpler and readable way of formatting strings in Python.The f-strings start with f prefix and use {} symbol to evaluate values.The python f-strings stands for python Formatted string literals.

Syntax

print(f"{var} constant.") 
# Python f string 
link = 'percentagetool.com'
print(f"{link } is a simple online website for percentage calculations.") 

Out Put 
percentagetool.com is a simple online website for percentage calculations

# Python f-string 

link = 'tutorialshore.com'
alexa=14999
print(f"{link} is a website with alexa rank {alexa}") 

Out Put 
tutorialshore.com is a website with alexa rank 14999
#using function in python f string 

def sum(x, y):

    return x + y

p = 8
q = 4

print(f'sum  of {p} and {q} is {sum(p, q)}')


Out put

sum  of 8 and 4 is 12

python get environment variable example code

An environment variable is simply a variable its values defined outside the application in this section we are going to explore how to get value of environment variable in python .so first we have to check how to set environment variable in python after that how to get that environment variable value.”print(os.environ)” is used to print all the value of all environment variable.

To work with environment variables in Python is the same like working with dictionaries. first you need to import the os module.

import os

/* To get the value of all environment variable value in python */

 

print(os.environ)

 

/* To set the environment variable value by name in python */

# To Set environment variables in python

os.environ['EMAIL'] = '[email protected]' 

os.environ['USER_ID'] = '4568'




/* To get the environment variable value by name in python */

 

# To get environment variables in python

import os
USER_EMAIL = os.environ.get('EMAIL') 
print(USER_EMAIL)
USER_ID = os.environ.get('USER_ID') 
print(USER_ID)