I have a list of dictionaries
lst = [ {'x': 1, 'y': 2}, {'x': 1, 'y': 3 }, {'x': 2, 'y': 2 } ]
Dictionaries always have the same keys and it is the values that change at all times.
So I would like to sum the value of the keys "y" when the key "x" has the same value.
The output should give:lst # [{'x': 1, 'y': 5 }, {'x': 2, 'y': 2 }].
I have a service declared in angular with the getSomeData() method in which I collect data from a json like so:
import { Injectable } from '@angular/core';
import {Http} from '@angular/http';
import { HttpModule } from '@angular/http';
import { Observable } from 'rxjs/Rx';
import "rxjs/add/operator/map";
import "rxjs/add/operator/filter";
@Injectable()
export class GetDataService {
constructor(private http: Http) { }
getSomeData() {
return this.http.get("dataTable.json")
.map(res => res.json());
}
}
In the component I have a variable data : any;to paint the data in the template.
When calling the subscribe service in the component with a normal javascript function like so, it doesn't show me the data with the response.
ngOnInit():void {
this._service.getSomeData().subscribe(
function(response) { this.data = JSON.stringify(response) },
function(error) { console.log("Error happened" + error)},
function() { console.log("the subscription is completed")}
);
}
However if I call the subscribe method with an Arrow Function if it paints the data:
ngOnInit():void {
this._service.getSomeData().subscribe(
response=>{
this.data = JSON.stringify(response);
}
err=>{
console.log("Error happened" + error)
}
);
}
I think it is a matter of asynchrony since with normal functions it does not have time to paint the data.
Can someone help me with this query? I have three tables with different names.
Tabla Ejemplo1
fecha campo1
2017-01-01 0.00
2017-01-01 7.00
2017-01-01 0.00
2017-01-01 1.00
2017-01-01 0.00
2017-01-02 1.00
2017-01-02 43.00
2017-01-02 1.00
2017-01-02 0.00
2017-01-02 0.00
Tabla Ejemplo2
fecha campo2
2017-01-01 0.00
2017-01-01 5.00
2017-01-01 1.00
2017-01-01 3.00
2017-01-01 0.00
2017-01-02 1.00
2017-01-02 3.00
2017-01-02 2.00
2017-01-02 2.00
2017-01-02 0.00
Tabla Ejemplo3
fecha campo3
2017-01-01 0.00
2017-01-01 5.00
2017-01-01 1.00
2017-01-01 3.00
2017-01-01 0.00
2017-01-02 1.00
2017-01-02 1.00
2017-01-02 0.00
2017-01-02 0.00
2017-01-02 0.00
I want to sum all the fields with their respective values and then join the dates in a date block. Like so...
Tabla Final
fecha campoTotal
2017-01-01 26.00
2017-01-02 55.00
I have tried two ways to do it with nested queries and with subqueries. And no way, I have come to do it. Someone might take me a cable?
queries
SELECT [fecha],
sum([campo1]) AS "campo1"
FROM Ejemplo1
WHERE fecha = '2017-01-01'
GROUP BY fecha
SELECT [fecha],
sum([campo2]) AS "campo2"
FROM Ejemplo2
WHERE fecha = '2017-01-01'
GROUP BY fecha
SELECT [fecha],
sum([campo3]) AS "campo3"
FROM Ejemplo3
WHERE fecha = '2017-01-01'
GROUP BY fecha
Subqueries
select fecha,sum(campo1) total
from
(
select fecha,campo1
from ejemplo1
union all
select fecha,campo2
from ejemplo2
union all
select fecha,campo3
from ejemplo3
) t
group by fecha
Why does python join two Stringwithout any kind of operator such as addition?
This:
>>> 'Perro' 'Lobo'
'PerroLobo'
It does the same as this:
>>> 'Perro' + 'Lobo'
'PerroLobo'
I have saved an object with .save()and I would like to get the id to update it after saving it, do you know any way to make a query on the same generated instance of the object.
I have tried the following code but it does not update me.
dash.save()
Dashboard.objects.filter(pk=dash).update(userInstance=userInstance)
I am trying to define the following function with Python,
def caja(cosas=[]):
cosas.append("lapiz")
cosas.append("martillo")
cosas.append("azulejos")
return cosas
>>> caja()
["lapiz", "martillo", "azulejos"]
Here comes the problem, when I call the function caja()again instead of creating an empty list, it adds the data to the existing list.
>>> caja()
["lapiz", "martillo", "azulejos","lapiz", "martillo", "azulejos"]
Does anyone know how Python works in this aspect? The arguments are only evaluated once at the time of declaring the function?
Thank you
Hello, I have a problem with an AJAX post request in jquery, since it generates two requests, one POST and the other OPTIONS, I don't know if this will be a problem in the long run or if the API gets confused.
Why does that OPTIONS request always appear? Could it be removed?
$.post("http://127.0.0.1:8000/newClient/", {
data: JSON.stringify(validData),
}, function (response) {
var r = JSON.parse(response);
if (r.status != 200) {
$('#err').html(r.content).css('color', 'red');
}
else {
$('#err').remove();
}
})
The API is in Django and these are the response headers it generates for me.
POST header
OPTIONS header
I want to know what this class is and how it works in Django.
class Categorias(models.Model):
...
class Meta:
...
Hello recently I have to generate a random and unique password for each user that I have in the Model.User.
I have tried with Python to generate numbers and letters with the libraries randomand string.
import random, string
pass = random.choice(string.ascii_uppercase + string.digits) for i in range(10)
But I think this is not efficient at all.
Django provide any solution?
I have a problem setting the Authorization header with the $.postjquery method.
$.post("http://127.0.0.1:8000/newClient/", {
beforeSend: function (xhr) {
xhr.setRequestHeader('Authorization','Basic ' + window.localStorage.getItem('token'));
},
data: JSON.stringify(validData)
}, function (response) {
console.log("Esto es el token ",window.localStorage.getItem('token'));
var r = JSON.parse(response);
console.log(r.status);
})
I have the token set correctly and I get it correctly in the response, I have made many AJAX requests with jquery but never with the method $.post, could it be that this method does not accept the header set?
Error trace.
Uncaught TypeError: Cannot read property 'setRequestHeader' of undefined
I have a huge MongoDB database and I want to generate the Django models dynamically so I don't do it by hand (it would save me a lot of work).
I have used inspectdb before to generate the models, but according to the official Django documentation, it is only available for relational databases ( PostgreSQL, MySQL and SQLite ).
Any alternative to generate models with MongoDB and import them into my models.py?