Decorator to automagically add placeholders to form widgets. `cls` can be any class derived from `django.forms.Form` or `django.forms.ModelForm`. The field labels are used as value for the placeholder. This will affect all form instances of this class.
* add_placeholders only to forms.TextInput and form.Textarea
* add_placeholders_to_any_field adds placeholders to any field
Usage:
@add_placeholders
class Form(forms.Form):
name = forms.CharField
The name field will render as `<input type="text" placeholder="name">`
rounds floats in more human readable format e.g.
341.123434 mUSD -> 341mUSD
0.45345345 mUSD -> 0.5 mUSD
0.034545 mUSD -> 0.03 mUSD
0.0014545 mUSD -> 0.001 mUSD
etc.
[DRF browsable API interface](http://www.django-rest-framework.org/api-guide/filtering/#customizing-the-interface) for django-rest-framework-gis [InBBoxFilter](https://github.com/djangonauts/django-rest-framework-gis#inbboxfilter)
Tested with
Django==1.10.5
django-filter==1.0.1
djangorestframework==3.5.4
djangorestframework-gis==0.11
"""
Takes arguments & constructs Qs for filter()
We make sure we don't construct empty filters that would return too many results
We return an empty dict if we have no filters so we can still return an empty response from the view
"""
Makes it possible to add a filtering condition directly after the aggregate function (or possible, `aggregate(expression) WITHIN GROUP (ordering clause)`. This is mostly useful if the annotation has two or more expressions, so it's possible to compare the result with and without the applied filter; it's more compact than using `Case`. It's suggested to add `values` to the queryset to get a proper group by.
Usage example:
`books = Book.objects.values('publisher__name').annotate(
count=Count('*'),
filtercount=Filter(expression=Count('publisher__name'),
condition=Q(rating__gte=5))
)
`
Supported on Postgresql 9.4+. Possible other third-party backends.
Small example of how to write your own function. This is not available in Django. The function just replaces static text strings, regular expressions are not supported.
The syntax is the same in SQLite, PostgreSQL, MySQL and Oracle.
The code was placed inside a helper file without using a class. The Django validator was not designed to work with validator classes, it would appear, so retrieving the value from the field proved to be a hassle. Just create a helper file, import it on your model, and use the validator in the standard way, as such:
cnpj = models.CharField(unique=True, max_length=14, validators=[validate_CNPJ])
cpf = models.CharField(unique=True, max_length=14, validators=[validate_CPF])
The function slices a queryset into smaller querysets containing chunk_size objects and then yield them.
It is used to avoid memory error when processing huge queryset, and also database error due to that the database pulls whole table at once.
Concurrent database modification wouldn't make some entries repeated or skipped in this process.