What is the difference between `gettext` and `gettext_lazy`?

The difference between gettext and gettext_lazy primarily lies in when the translation of the string occurs:

1. gettext:
   • Immediate Translation: The translation happens immediately when the function is called. The string is translated at runtime as soon as the function executes.
   • Usage: This is suitable for situations where the string needs to be translated right away, such as in view functions, immediate responses, or any context where the translation does not need to be delayed.

   from django.utils.translation import gettext as _

   translated_string = _("Hello, world!")

1. gettext_lazy:
   • Lazy Translation: The translation is deferred until the string is actually used. The string is marked for translation, but the actual translation does not happen until the string is accessed, such as in template rendering or form field definitions.
   • Usage: This is suitable for situations where the translation might not need to happen immediately, such as model field definitions, form field labels, or anywhere the translation can wait until the string is rendered or used later.

   from django.utils.translation import gettext_lazy as _

   translated_string = _("Hello, world!")

Practical Examples:

Using gettext:

from django.utils.translation import gettext as _

def greet_user():
    greeting = _("Hello, world!")  # Translated immediately
    return greeting

Using gettext_lazy:

from django.utils.translation import gettext_lazy as _
from django.db import models

class MyModel(models.Model):
    name = models.CharField(max_length=100, verbose_name=_("Name"))  # Translation is deferred

class MyForm(forms.Form):
    name = forms.CharField(label=_("Name"))  # Translation is deferred

Summary:

• gettext is used when you need the translation to occur right away.
• gettext_lazy is used when you need the translation to occur later, which is common in Django models, forms, and other parts of the code where the string might be rendered at a different time than when it is defined.