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Open source softwares - Django

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Lesson Description


Lession - #1015 django_if_else

If Statement

An if statement evaluates a variable and executes a block of code assuming the value is valid.
Example
{% if greeting == 1 %}
  <h1>Hello</h1>
{% endif %}

Elif

The elif keyword says "on the off chance that the past conditions were false, then attempt this condition".
Example
{% if greeting == 1 %}
  <h1>Hello</h1>
{% elif greeting == 2 %}
  <h1>Welcome</h1>
{% endif %}

Else

The else keyword finds anything which isn't gotten by the preceding conditions.
Example
{% if greeting == 1 %}
  <h1>Hello</h1>
{% elif greeting == 2 %}
  <h1>Welcome</h1>
{% else %}
  <h1>Goodbye</h1>
{% endif %}

Operators

The above models utilizes the == operator, which is utilized to check if a variable is equivalent to a value, however there are numerous different operators you can utilize, or you could drop the operator if you just want to check if a variable isn't vacant:

Example
{% if greeting %}
  <h1>Hello</h1>
{% endif %}

==

Is equal to 
Example
{% if greeting == 2 %}
  <h1>Hello</h1>
{% endif %}

!=

Is not equal to. 
Example
{% if greeting != 1 %}
  <h1>Hello</h1>
{% endif %}

<

Is less than 
Example
{% if greeting < 3 %}
   <h1>Hello</h1>
{% endif %}

<=

Is less than, or equal to. 
Example
{% if greeting <= 3 %}
  <h1>Hello</h1>
{% endif %}

>

Is greater than 
Example
{% if greeting > 1 %}
  <h1>Hello</h1>
{% endif %}

>=

Is greater than, or equal to. 
Example
{% if greeting >= 1 %}
  <h1>Hello</h1>
{% endif %}

and

To check if more than one condition is true. 
Example
{% if greeting == 1 and day == "Friday" %}
  <h1>Hello Weekend!</h1>
{% endif %}

or

To check if one of the conditions is true. 
Example
{% if greeting == 1 or greeting == 5 %}
  <h1>Hello</h1>
{% endif %}

and/or

combine and and or 
Example
{% if greeting == 1 and day == "Friday" or greeting == 5 %}

in

To check if a certain item is present in an object. 
Example
{% if 'Banana' in fruits %}
  <h1>Hello</h1>
{% else %}
  <h1>Goodbye</h1>
{% endif %}

not in

To check if a certain item is not present in an object. 
Example
{% if 'Banana' not in fruits %}
   <h1>Hello</h1>
{% else %}
  <h1>Goodbye</h1>
{% endif %}

is

Check in the event that two items are something similar.

This operator is not quite the same as the == operator, on the grounds that the == operator really takes a look at the upsides of two items, however the is operator really takes a look at the personality of two items.

In the view we have two articles, x and y, with similar qualities: 
Example
views.py
from django.http import HttpResponse
from django.template import loader

def testing(request>
:
  template = loader.get_template('template.html'>

  context = {
    'x': ['Apple', 'Banana', 'Cherry'], 
    'y': ['Apple', 'Banana', 'Cherry'], 
  }
  return HttpResponse(template.render(context, request>
>

is not

Example
{% if x is not y %}
  <h1>YES<h1>
{% else %}
  <h1>NO</h1>
{% endif %}