I don't know how set name for this question.. sorry.
I have function:
myFunction(request, {'Username': 'MyNewUsername', 'Sex': 'Woman', 'SexWant': 'Man'})
def myFunction(self, data):
dataquery = UserData.objects.get(Username = "Patrycja")
for name, key in data.items():
dataquery.name = key
dataquery.save()
Generally speaking this line: dataquery.name
name is 'Username', if I set dataquery.Username = good. But I have to do it as above
From what I understand, your query should be
dataquery = UserData.objects.get(username="Patrycja")
then be aware that the line
dataquery.name = key
sets the attribute name of the object.
In order to set the attributes whose name is specified in data you need to use setattr
for name, value in data.items():
setattr(dataquery, name, value)
and since you seem to want to update only such fields, call save specifing which fields should be updated
dataquery.save(update_fields=data.keys())
Note: please refer to #Sayse's answer in case you need to update more than one record at a time
Related
Suppose I have a python class like:
class User:
name = None
id = None
dob = None
def __init__(self, id):
self.id = id
Now I am doing something like this:
userObj = User(id=12) # suppose I don't have values for name and dob yet
## some code here and this code gives me name and dob data in dictionary, suppose a function call
user = get_user_data() # this returns the dictionary like {'name': 'John', 'dob': '1992-07-12'}
Now, the way to assign data to user object is userObj.name = user['name'] and userObj.dob = user['dob']. Suppose, User has 100 attributes. I will have to explicitly assign these attributes. Is there an efficient way in Python which I can use to assign the values from a dictionary to the corresponding attributes in the object? Like, name key in the dictionary is assigned to the name attribute in the object.
1. Modify the Class definition
class User():
def __init__(self, id):
self.data = {"id":id}
userObj = User(id=12)
2. Update the dict()
user = {"name":"Frank", "dob":"Whatever"} # Get the remaining data from elsewhere
userObj.data.update(user) # Update the dict in your userObj
print(userObj.data)
Here you go !
Instead of mapping a dict to the variable keys. You can use setattr to set variables in an object.
class User:
name = None
id = None
dob = None
def __init__(self, id):
self.id = id
def map_dict(self, user_info):
for k, v in user_info.items():
setattr(self, k, v)
Then for boiler code to use it.
userObj = User(id=12)
user_dict = {
'name': 'Bob',
'dob': '11-20-1993',
'something': 'blah'
}
userObj.map_dict(user_dict)
First, there is no need to predeclare properties in python.
class Foo:
bar: int # This actually creates a class member, not an instance member
...
If you want to add values to a class instance just use setattr()
d = {
'prop1': 'value1',
'prop2': 'value2',
'prop2': 'value2'
}
x = Foo()
for prop in d.keys():
setattr(x, prop, d[prop])
class User(dict):
def __init__(self, *args, **kwargs):
super(User, self).__init__(*args, **kwargs)
self.__dict__ = self
and then just get your dictionary and do:
userObj = User(dictionary)
EDIT:
user the function setattr() then
[setattr(userObj, key, item) for key,item in dict.items()]
In Case you REALLY need to
This solution is for the case, other solutions dont work for you and you cannot change your class.
Issue
In case you cannot modify your class in any way and you have a dictionary, that contains the information you want to put in your object, you can first get the custom members of your class by using the inspect module:
import inspect
import numpy as np
members = inspect.getmembers(User)
Extract your custom attributes from all members by:
allowed = ["__" not in a[0] for a in members]
and use numpy list comprehention for the extraction itself:
members = np.array(members)["__" not in a[0] for a in members]
Modify the user
So lets say you have the following user and dict and you want to change the users attributes to the values in the dictionary (behaviour for creating a new user is the same)
user = User(1)
dic = {"name":"test", "id": 2, "dob" : "any"}
then you simply use setattr():
for m in members:
setattr(user, m[0], dic[m[0]])
For sure there are better solutins, but this might come in handy in case other things dont work for you
Update
This solution uses the attribute definitions based on your class you use. So in case the dictionary has missing values, this solution might be helpful. Else Rashids solution will work well for you too
I want to get the field names in a model to be an option in a selection field in another model. Is it possible?
class ExportEmplWizard(models.TransientModel):
_name = 'hr.empl.exp.wizard'
empl_ids = fields.Many2many('hr.employee', string="Karyawan")
hr_field = fields.Selection(hr_field_choice, string="Pilih Kolom")
def empl_to_exp(self):
fields = self.env['hr.employee'].fields_get()
hr_field_choices = []
for key, val in fields.items():
choice = (key, val['string'])
hr_field_choices.append(choice)
I'm trying get fields name on other model using:
sel.self.env['hr.employee'].fields_get()
The problem is, i don't know how to make it as selection options (multiple selection actually).
Thank you for the help.
As per docstring for fields.Selection()
:param selection: specifies the possible values for this field.
It is given as either a list of pairs (value, string), or a
model method, or a method name.
Basically, the selection argument should work like the compute argument. And code of fields.Selection.get_values() confirms this.
So you should try something like this :
hr_field = fields.Selection(selection='empl_to_exp', string="Pilih Kolom")
def empl_to_exp(self):
fields = self.env['hr.employee'].fields_get()
return [(k, v['string']) for k, v in fields.items()]
You may have/want to use getattr(v, 'string', 'DEFAULT_VALUE') instead of simply v['string']. Fields should always have a string though.
def get_selection_name(env, model, field, value):
return dict(env[model].fields_get(field, 'selection').get(field, {}).get('selection',{})).get(value)
# usage
get_selection_name(request.env, 'sale.order', 'general_status', 'draft') # 'Draft'
get_selection_name(self.env, 'sale.order', 'general_status', 'draft') # 'Draft'
I use this!
How can I use getattr without "Class" per se ?
So I have this situation: I have 'columns' that are asking mysql for specific data in a specific order. data is printed via flask/apache so that user has ability to manipulate this data. Now, From flask, POST methdd, I'm receiving changed(?) values and I am storing them in python attributes.I need to check if values within those attributes are same as in original data. Sure, I could hardcore it but I would like have possibility of change columns dynamically.
columns = ["username", "email", "admin"]
data = ("john", "john#snow.com", "True")
username = "john"
email = "different#email.com"
admin = False
Not sure how can I approach it ?
for i in data:
if i == getattr(???, 'username'):
print("it's the same")
or something like this?:
for i in data:
if i == getattr(data, '?????'):
print("it's the same")
Everything is within flask, I cannot embed it into the Class per se. So I don't have 'self' etc.
If I could create class I would probably make something like
class Myclass:
def __init__(self):
self.columns = ["username", "email", "admin"]
self.data = ("john", "john#snow.com", "True")
self.result = []
self.username = "john"
self.email = "different#email.com"
self.admin = False
def test(self):
for i in self.data:
if i == getattr(self, self.columns[self.data.index(i)]):
self.result.append("same")
else:
self.result.append("different")
return self.result
Myclass().test()
['same', 'different', 'different']
It turned out that I was looking for simple eval(). getattr() is designed for different purposes.
so simple:
for i in data:
if i == eval(cols[data.index(i)]):
print("it's the same")
did the trick
Flask is just Python code. You can create a class and use that if that fits your use-case. Or, if you used Flask-SQLAlchemy to manage database-backed data you'd have classes and instances anyway (and get easier data updates to boot).
And classes and instances are not the only objects with attributes; modules and functions have attributes too (although you wouldn't store your data as attributes on either of those), and when you look up methods on anything, you are looking up attributes too.
Pick a storage, then either wrap that storage with an instance of a class, and use getattr(), or pick a different data structure and use the methods for that data structure to get at the different fields. A dictionary, for instance, would make it trivial to get the current value for a given name.
If you do stick to instances, then note that in your loop you'd want to zip your columns and data values together:
for name, value in zip(columns, data):
if getattr(self, name) == value:
self.result.append("same")
else:
self.result.append("different")
Note that you do not have to add "self." in front, the whole point of getattr() is do the same work the . syntax does.
You probably want to put your columns and data lists together as a dictionary:
self.data = {'username': 'john', 'email': 'john#snow.com', 'admin': 'True'}
because that's how you'd process POST data from a form anyway; that way you can iterate over the dict.items() pairs, or use just the columns list to access values:
for name, value in self.data.items():
# ...
or use dict.get() to retrieve values, allowing for missing entries:
for name in self.columns:
if getattr(self, name) == self.data.get(name):
# ...
Model:
db.define_table('orders',
Field('customer_id', db.customer)
Field('order_id', 'string')
)
I want to get a special order_id like XY-150012 where XY is part of the customer name, 15 is the year and 12 the id the actual record-id of orders. I tried in the model:
db.orders.order_id.compute = lambda r: "%s-%s00%s" % (db.customer(r['customer_id']).short, str(request.now.year)[2:], r['id'])
The id is never recognized, the computation ends up as None. If I remove r['id'] from the compute-line it works.
EDIT:
After adding an extra field field('running_number', 'integer') to the model I can access this fields content.
Is there a easy way to set this fields default=db.orders.id?
SOLUTION:
With Anthony´s Input, and reading about recursive selects I came up with this solution:
db.define_table('orders',
Field('customer_id', db.customer),
Field('order_id', 'string', default = None))
def get_order_id(id, short):
y = str(request.now.year)[2:]
return '%s-%s00%s' % (short, y, id)
def set_id_after_insert(fields,id):
fields.update(id=id)
def set_order_id_after_update(s,f):
row = s.select().first()
if row['order_id'] == None:
s.update_naive(order_id=get_order_id(row['id'], row['customer_id'].short)
else:
return
db.orders._after_insert.append(lambda f,id: set_id_after_insert(f,id))
db.orders._after_update.append(lambda s,f: set_order_id_after_update(s,f))
The problem is that the record ID is not known until after the record has been inserted in the database, as the id field is an auto-incrementing integer field whose value is generated by the database, not by web2py.
One option would be to define an _after_insert callback that updates the order_id field after the insert:
def order_after_insert(fields, id):
fields.update(id=id)
db(db.order.id == id).update(order_id=db.order.order_id.compute(fields))
db.order._after_insert.append(order_after_insert)
You might also want to create an _after_update callback, but in that case, be sure to use the update_naive argument in both callbacks when defining the Set (see above link for details).
Depending on how the order_id is used, another option might be a virtual field.
I want to create a new type of field for django models that is basically a ListOfStrings. So in your model code you would have the following:
models.py:
from django.db import models
class ListOfStringsField(???):
???
class myDjangoModelClass():
myName = models.CharField(max_length=64)
myFriends = ListOfStringsField() #
other.py:
myclass = myDjangoModelClass()
myclass.myName = "bob"
myclass.myFriends = ["me", "myself", "and I"]
myclass.save()
id = myclass.id
loadedmyclass = myDjangoModelClass.objects.filter(id__exact=id)
myFriendsList = loadedclass.myFriends
# myFriendsList is a list and should equal ["me", "myself", "and I"]
How would you go about writing this field type, with the following stipulations?
We don't want to do create a field which just crams all the strings together and separates them with a token in one field like this. It is a good solution in some cases, but we want to keep the string data normalized so tools other than django can query the data.
The field should automatically create any secondary tables needed to store the string data.
The secondary table should ideally have only one copy of each unique string. This is optional, but would be nice to have.
Looking in the Django code it looks like I would want to do something similar to what ForeignKey is doing, but the documentation is sparse.
This leads to the following questions:
Can this be done?
Has it been done (and if so where)?
Is there any documentation on Django about how to extend and override their model classes, specifically their relationship classes? I have not seen a lot of documentation on that aspect of their code, but there is this.
This is comes from this question.
There's some very good documentation on creating custom fields here.
However, I think you're overthinking this. It sounds like you actually just want a standard foreign key, but with the additional ability to retrieve all the elements as a single list. So the easiest thing would be to just use a ForeignKey, and define a get_myfield_as_list method on the model:
class Friends(model.Model):
name = models.CharField(max_length=100)
my_items = models.ForeignKey(MyModel)
class MyModel(models.Model):
...
def get_my_friends_as_list(self):
return ', '.join(self.friends_set.values_list('name', flat=True))
Now calling get_my_friends_as_list() on an instance of MyModel will return you a list of strings, as required.
What you have described sounds to me really similar to the tags.
So, why not using django tagging?
It works like a charm, you can install it independently from your application and its API is quite easy to use.
I also think you're going about this the wrong way. Trying to make a Django field create an ancillary database table is almost certainly the wrong approach. It would be very difficult to do, and would likely confuse third party developers if you are trying to make your solution generally useful.
If you're trying to store a denormalized blob of data in a single column, I'd take an approach similar to the one you linked to, serializing the Python data structure and storing it in a TextField. If you want tools other than Django to be able to operate on the data then you can serialize to JSON (or some other format that has wide language support):
from django.db import models
from django.utils import simplejson
class JSONDataField(models.TextField):
__metaclass__ = models.SubfieldBase
def to_python(self, value):
if value is None:
return None
if not isinstance(value, basestring):
return value
return simplejson.loads(value)
def get_db_prep_save(self, value):
if value is None:
return None
return simplejson.dumps(value)
If you just want a django Manager-like descriptor that lets you operate on a list of strings associated with a model then you can manually create a join table and use a descriptor to manage the relationship. It's not exactly what you need, but this code should get you started.
Thanks for all those that answered. Even if I didn't use your answer directly the examples and links got me going in the right direction.
I am not sure if this is production ready, but it appears to be working in all my tests so far.
class ListValueDescriptor(object):
def __init__(self, lvd_parent, lvd_model_name, lvd_value_type, lvd_unique, **kwargs):
"""
This descriptor object acts like a django field, but it will accept
a list of values, instead a single value.
For example:
# define our model
class Person(models.Model):
name = models.CharField(max_length=120)
friends = ListValueDescriptor("Person", "Friend", "CharField", True, max_length=120)
# Later in the code we can do this
p = Person("John")
p.save() # we have to have an id
p.friends = ["Jerry", "Jimmy", "Jamail"]
...
p = Person.objects.get(name="John")
friends = p.friends
# and now friends is a list.
lvd_parent - The name of our parent class
lvd_model_name - The name of our new model
lvd_value_type - The value type of the value in our new model
This has to be the name of one of the valid django
model field types such as 'CharField', 'FloatField',
or a valid custom field name.
lvd_unique - Set this to true if you want the values in the list to
be unique in the table they are stored in. For
example if you are storing a list of strings and
the strings are always "foo", "bar", and "baz", your
data table would only have those three strings listed in
it in the database.
kwargs - These are passed to the value field.
"""
self.related_set_name = lvd_model_name.lower() + "_set"
self.model_name = lvd_model_name
self.parent = lvd_parent
self.unique = lvd_unique
# only set this to true if they have not already set it.
# this helps speed up the searchs when unique is true.
kwargs['db_index'] = kwargs.get('db_index', True)
filter = ["lvd_parent", "lvd_model_name", "lvd_value_type", "lvd_unique"]
evalStr = """class %s (models.Model):\n""" % (self.model_name)
evalStr += """ value = models.%s(""" % (lvd_value_type)
evalStr += self._params_from_kwargs(filter, **kwargs)
evalStr += ")\n"
if self.unique:
evalStr += """ parent = models.ManyToManyField('%s')\n""" % (self.parent)
else:
evalStr += """ parent = models.ForeignKey('%s')\n""" % (self.parent)
evalStr += "\n"
evalStr += """self.innerClass = %s\n""" % (self.model_name)
print evalStr
exec (evalStr) # build the inner class
def __get__(self, instance, owner):
value_set = instance.__getattribute__(self.related_set_name)
l = []
for x in value_set.all():
l.append(x.value)
return l
def __set__(self, instance, values):
value_set = instance.__getattribute__(self.related_set_name)
for x in values:
value_set.add(self._get_or_create_value(x))
def __delete__(self, instance):
pass # I should probably try and do something here.
def _get_or_create_value(self, x):
if self.unique:
# Try and find an existing value
try:
return self.innerClass.objects.get(value=x)
except django.core.exceptions.ObjectDoesNotExist:
pass
v = self.innerClass(value=x)
v.save() # we have to save to create the id.
return v
def _params_from_kwargs(self, filter, **kwargs):
"""Given a dictionary of arguments, build a string which
represents it as a parameter list, and filter out any
keywords in filter."""
params = ""
for key in kwargs:
if key not in filter:
value = kwargs[key]
params += "%s=%s, " % (key, value.__repr__())
return params[:-2] # chop off the last ', '
class Person(models.Model):
name = models.CharField(max_length=120)
friends = ListValueDescriptor("Person", "Friend", "CharField", True, max_length=120)
Ultimately I think this would still be better if it were pushed deeper into the django code and worked more like the ManyToManyField or the ForeignKey.
I think what you want is a custom model field.