In my first attempt to develop something in Ruby on Rails :) ... I have a list of names stored in fields "first_name" and "last_name". In my Person model, I have defined something like this:
def sort_name
sort_name = last_name + ',' + first_name
end
Now I want to show all persons shown in a list, sorted by sort_name, but (in my controller) something like
#persons = Person.order(:sort_name)
doesn't work (Unknown column 'sort_name' in 'order clause'). How do reference to the calculated field sort_name in my controller?
I am sure this is a "oh my god I am so stupid moment" but happy for any advise!
If the model Person has the fields name, first_lastname and second_lastname, you can do the next:
Person.order(:name, :first_lastname, :second_lastname)
By default is ordering in ascending way. Also you can put if you want ascending or descending way for each field:
Person.order(name: :asc, first_lastname: :desc, second_lastname: :asc)
Additional if you want add a column with the complete name, you can use select, using postgresql the code would be:
people = Person.order(
name: :asc, first_lastname: :desc, second_lastname: :asc
).select(
"*, concat(name,' ', first_lastname, ' ',second_lastname) as sort_name"
)
people[0].sort_name
# the sort_name can be for example "Adán Saucedo Salas"
Related
Is it possible to put a filter into the Issue model whose items are getting counted here????
issues = Student.objects.annotate(Count('issue'))
I really need to filter it so as to get the desired outcome...
If not is there a way I can be able to get count of all Issues to a particular student?
class Issue(SafeDeleteModel):
_safedelete_policy = SOFT_DELETE
borrower_id = models.ForeignKey(Student,on_delete=models.CASCADE)
book_id = models.ForeignKey(Books,on_delete=models.CASCADE)
class Student(models.Model):
school = models.ForeignKey(School, on_delete=models.CASCADE)
name = models.CharField(max_length=200)
student_id = models.CharField(max_length=20)
Yes, you can filter what items are counted with the filter=… parameter [Django-doc]. We can for example filter on the book_id with:
issues = Student.objects.annotate(
num_issues=Count(
'issue',
filter=Q(issue__book_id_id=some_book_id)
)
)
or to exclude soft deleted items, we can work with the deleted field that has been defined in your model (by the django-safedelete package):
issues = Student.objects.annotate(
num_issues=Count(
'issue',
filter=Q(issue__deleted=False)
)
)
Note: Normally one does not add a suffix _ids to a ManyToManyField field, since Django
it refers to a manager over the target objects. Therefore it should
be book, instead of book_id.
I'm new to Lua (like, yesterday new), so please bear with me...
I apologize for the convoluted nature of this question, but I had no better idea of how to demonstrate what I'm trying to do:
I have a Lua table being used as a dictionary. The tuples(?) are not numerically indexed, but use mostly string indices. Many of the indices actually relate to sub-tables that contain more detailed information, and some of the indices in those tables relate to still more tables - some of them three or four "levels" deep.
I need to make a function that can search for a specific item description from several "levels" into the dictionary's structure, without knowing ahead of time which keys/sub-keys/sub-sub-keys led me to it. I have tried to do this using variables and for loops, but have run into a problem where two keys in a row are being dynamically tested using these variables.
In the example below, I'm trying to get at the value:
myWarehouselist.Warehouse_North.departments.department_one["rjXO./SS"].item_description
But since I don't know ahead of time that I'm looking in "Warehouse_North", or in "department_one", I run through these alternatives using variables, searching for the specific Item ID "rjXO./SS", and so the reference to that value ends up looking like this:
myWarehouseList[warehouse_key].departments[department_key][myItemID]...?
Basically, the problem I'm having is when I need to put two variables back-to-back in the reference chain of a value being stored at level N of a dictionary. I can't seem to write it out as [x][y], or as [x[y]], or as [x.y] or as [x].[y]... I understand that in Lua, x.y is not the same as x[y] (the former directly references a key by string index "y", while the latter uses the value being stored in variable "y", which could be anything.)
I've tried many different ways and only gotten errors.
What's interesting is that if I use the exact same approach, but add an additional "level" to the dictionary with a constant value, such as ["items"] (under each specific department), it allows me to reference the value without issue, and my script runs fine...
myWarehouseList[warehouse_key].departments[department_key].items[item_key].item_description
Is this how Lua syntax is supposed to look? I've changed the table structure to include that extra layer of "items" under each department, but it seems redundant and unnecessary. Is there a syntactical change that I can make to allow me to use two variables back-to-back in a Lua table value reference chain?
Thanks in advance for any help!
myWarehouseList = {
["Warehouse_North"] = {
["description"] = "The northern warehouse"
,["departments"] = {
["department_one"] = {
["rjXO./SS"] = {
["item_description"] = "A description of item 'rjXO./SS'"
}
}
}
}
,["Warehouse_South"] = {
["description"] = "The southern warehouse"
,["departments"] = {
["department_one"] = {
["rjXO./SX"] = {
["item_description"] = "A description of item 'rjXO./SX'"
}
}
}
}
}
function get_item_description(item_id)
myItemID = item_id
for warehouse_key, warehouse_value in pairs(myWarehouseList) do
for department_key, department_value in pairs(myWarehouseList[warehouse_key].departments) do
for item_key, item_value in pairs(myWarehouseList[warehouse_key].departments[department_key]) do
if item_key == myItemID
then
print(myWarehouseList[warehouse_key].departments[department_key]...?)
-- [department_key[item_key]].item_description?
-- If I had another level above "department_X", with a constant key, I could do it like this:
-- print(
-- "\n\t" .. "Item ID " .. item_key .. " was found in warehouse '" .. warehouse_key .. "'" ..
-- "\n\t" .. "In the department: '" .. dapartment_key .. "'" ..
-- "\n\t" .. "With the description: '" .. myWarehouseList[warehouse_key].departments[department_key].items[item_key].item_description .. "'")
-- but without that extra, constant "level", I can't figure it out :)
else
end
end
end
end
end
If you make full use of your looping variables, you don't need those long index chains. You appear to be relying only on the key variables, but it's actually the value variables that have most of the information you need:
function get_item_description(item_id)
for warehouse_key, warehouse_value in pairs(myWarehouseList) do
for department_key, department_value in pairs(warehouse_value.departments) do
for item_key, item_value in pairs(department_value) do
if item_key == item_id then
print(warehouse_key, department_key, item_value.item_description)
end
end
end
end
end
get_item_description'rjXO./SS'
get_item_description'rjXO./SX'
I have a dictionary of phone numbers where number is Key and country is value. I want to update the key and add country code based on value country. I tried to use the map function for this:
print('**Exmaple: Update phone book to add Country code using map function** ')
user=[{'952-201-3787':'US'},{'952-201-5984':'US'},{'9871299':'BD'},{'01632 960513':'UK'}]
#A function that takes a dictionary as arg, not list. List is the outer part
def add_Country_Code(aDict):
for k,v in aDict.items():
if(v == 'US'):
aDict[( '1+'+k)]=aDict.pop(k)
if(v == 'UK'):
aDict[( '044+'+k)]=aDict.pop(k)
if (v == 'BD'):
aDict[('001+'+k)] =aDict.pop(k)
return aDict
new_user=list(map(add_Country_Code,user))
print(new_user)
This works partially when I run, output below :
[{'1+952-201-3787': 'US'}, {'1+1+1+952-201-5984': 'US'}, {'001+9871299': 'BD'}, {'044+01632 960513': 'UK'}]
Notice the 2nd US number has 2 additional 1s'. What is causing that?How to fix? Thanks a lot.
Issue
You are mutating a dict while iterating it. Don't do this. The Pythonic convention would be:
Make a new_dict = {}
While iterating the input a_dict, assign new items to new_dict.
Return the new_dict
IOW, create new things, rather than change old things - likely the source of your woes.
Some notes
Use lowercase with underscores when defining variable names (see PEP 8).
Lookup values rather than change the input dict, e.g. a_dict[k] vs. a_dict.pop(k)
Indent the correct number of spaces (see PEP 8)
I have a search request written as
import sqlite3
conn = sqlite3.connect('locker_data.db')
c = conn.cursor()
def search1(teacher):
test = 'SELECT Name FROM locker_data WHERE Name or Email LIKE "%{0}%"'.format(teacher)
data1 = c.execute(test)
return data1
def display1(data1):
Display1 = []
for Name in data1:
temp1 = str(Name[0])
Display1.append("Name: {0}".format(temp1))
return Display1
def locker_searcher(teacher):
data = display1(search1(teacher))
return data
This allows me to search for the row containing "Mr FishyPower (Mr Swag)" or "Mr FishyPower / Mr Swag" with a search input of "FishyPower". However, when I try searching with an input of "Swag", I am then unable to find the same row.
In the search below, it should have given me the same search results.
The database is just a simple 1x1 sqlite3 database containing 'FishyPower / Mr Swag'
Search Error on 'Swag'
Edit: I technically did solve it by limiting the columns being searched to only 'Name' but I intended the code search both the 'Name' and 'Email' columns and output the results as long as the search in within either or both columns.
Edit2: SELECT Name FROM locker_data WHERE Email LIKE "%{0}%" or Name LIKE "%{0}%" was the right way to go.
I'm gonna guess that Mr. FishyPower's email address is something like mrFishyPower#something.com. The query is only comparing Email to teacher. If it was
WHERE Name LIKE "%{0}%"
OR Email LIKE "%{0}%"'
you would (probably) get the result you want.
Hi I am trying to get some referenced data from another table,
Data structure:
Table PartDetail
-id
-OperationTypeID(foreign key)
-DateAdded
Table OperationType
-id
-Description
I am trying something like this:
$crud = $this->add('MVCGrid', array('allow_edit'=>false));
$crud->setModel('Model_PartDetail',array('DateAdded'));
But then I want to see the "description" from table OperationType, because on my PartDetail model I declare my relationship like this:
$this->hasOne('OperationType','OperationTypeID','Description')
->mandatory(true)
->caption('Operation Type');
for example in this case I want to see the description from the table OperationType
I tried:
$crud->setModel('Model_PartDetail',array('DateAdded','OperationType'));
but is not working, only works with:
$crud->setModel('Model_PartDetail',array('DateAdded','OperationTypeID'));
but I get only the ID number, not the description.
How this works?
I was able to solved it.
on the model you need to redefine it as
$ref = $this->add('Field_Reference', 'OperationTypeID');
$ref->dereferenced_field='OperationTypeDescription';
$m = $this->add('Model_OperationType');
$m->addField('D'); // <-- actually seems that this line is not working
$ref->setModel($m, 'Description');
And then in the page you can actually added as OperationTypeDescription:
$crud->setModel('Model_PartDetail', array('DateAdded', 'OperationTypeDescription'));