How to access class variable in Python?

Question

I'm new to Python programming and wondering how can I access to variables I have declared in one file to another? I'm working on Django and have two files:

1. forms.py

    class ContactForm(forms.Form): full_name = forms.CharField(max_length=100) email = forms.EmailField() message = forms.CharField(max_length=1000) 

2. views.py

    from .forms import ContactForm def contact(request): e = ContactForm() toPrint = e.get(email) print(toPrint) 

I'm just testing it to print on terminal to help me learn how to access those variables to use them in views.py

Answer 1

in the views you would normally pass in the data that went into the form then you can grab it with cleaned_data like this

def contact(request):
    context = {}
    if request.method == 'POST':
        form = ContactForm(data=request.POST)
        if form.is_valid():
            email = form.cleaned_data.get('email', '')
            # do something with email here??
    else:
        form = ContactForm()
    context['form'] = form
    return render(request, 'signup.html', context)

Answer 2

EDIT: As was pointed out in the comments, this answer does not work in the specific case of django, because of some django-magic. But in general this should be correct.

First of, you should declare the variables in the __init__ function (the constructor) of the ContactForm class. Then you store it under self :

class ContactForm(forms.Form):
    def __init__(self):
        super().__init__()
        self.full_name = forms.CharField(max_length=100)
        self.email = forms.EmailField()
        self.message = forms.CharField(max_length=1000)

In either case (if you keep the code like you have it, or you use the constructor function explicitly), you access the variables simply as

e = ContactForm()
to_print = e.email
....

Answer 3

e = ContactForm()

如果您的表格经过验证，则可以通过

e.cleaned_data.get('email')

Answer 4

Django forms use a so-called metaclass. What this does in this specific case is capture all Field instance defined on the form, and put them in a dictionary called declared_fields . You can see the source code here . You would access the original field as ContactForm.declared_fields['email'] .

The form makes a copy of declared_fields and puts it in the fields attribute to allow changes to fields in a single form instance. You would then access the fields as follows:

e = ContactForm()
e.fields['email']

As said by others, if it weren't for the metaclass, you would just use ContactForm.email or e.email .