Conditional average with numpy

Question

Given a 2x3 array, I want to calculate the average on """colors URL Configuration The `urlpatterns` list routes URLs to views. For more information please see: https://docs.djangoproject.com/en/1.11/topics/http/urls/ Examples: Function views 1. Add an import: from my_app import views 2. Add a URL to urlpatterns: url(r'^$', views.home, name='home') Class-based views 1. Add an import: from other_app.views import Home 2. Add a URL to urlpatterns: url(r'^$', Home.as_view(), name='home') Including another URLconf 1. Import the include() function: from django.conf.urls import url, include 2. Add a URL to urlpatterns: url(r'^blog/', include('blog.urls')) """ from django.conf.urls import url from django.contrib import admin from django.conf.urls import include from accounts import views from colorsets import views urlpatterns = [ url(r'^admin/', admin.site.urls), url(r'^$',views.PostListView.as_view(),name='index'), url(r'^accounts/',include('accounts.urls',namespace='accounts')), url(r'^colorsets/',include('colorsets.urls',namespace='colorsets')), ] , but only considering values that are larger than 0.

So given the array

{% extends 'base.html' %}

{% block content %}
    <h3>Are you sure you want to delete this post?</h3>

    <div class="posts">
        {% include "colorsets/_post.html" with post=object hide_delete=True %}
    </div>
    <form method="POST">
        {% csrf_token %}
        <input type="submit" value="Confirm Delete" class="btn btn-danger btn-large" />
        <a class="btn btn-simple btn-large" href="{% url 'index' username=user.username pk=object.pk %}">Cancel</a>
    </form>
{% endblock %}

I want the output to be

{% extends "base.html" %}

{% block content %}

<div class="container">
    <div class="sidebar">
        <div class="widget widget-one">
            <div class="widget-content">
                {% if user.is_authenticated %}
                    <p>Welcome, {{ user.username }}</p>
                {% endif %}
            </div>
        </div>

        <div class="widget widget-two">
            <p>Widget Two</p>
        </div>

        <div class="widget widget-three">
            <p>Widget Three</p>
        </div>
    </div>

    <div class="content">
    {% for colorset in colorset_list %}
            <table class="colorset">
                <tr>
                    <h3 class="set-name">{{ colorset.name }}</h3>
                    <p class="author accent-text">Author: {{ colorset.user }}</p>

                    {% if user.is_authenticated and colorset.user == user %}
                        <a href="{% url 'colorsets:delete' pk=colorset.pk %}" title="delete" class="btn btn-simple">
                            <span class="text-danger icon-label">Delete</span>
                        </a>
                    {% endif %}

                    <td class="color" style="background-color:#{{ colorset.color_one }}">
                    </td>
                    <td class="color" style="background-color:#{{ colorset.color_two }}">
                    </td>
                    <td class="color" style="background-color:#{{ colorset.color_three }}">
                    </td>
                    <td class="color" style="background-color:#{{ colorset.color_four }}">
                    </td>
                    <td class="color" style="background-color:#{{ colorset.color_five }}">
                    </td>
                </tr>
                <tr>
                    <td>
                        <p>#{{ colorset.color_one }}</p>
                    </td>
                    <td>
                        <p>#{{ colorset.color_two }}</p>
                    </td>
                    <td>
                        <p>#{{ colorset.color_three }}</p>
                    </td>
                    <td>
                        <p>#{{ colorset.color_four }}</p>
                    </td>
                    <td>
                        <p>#{{ colorset.color_five }}</p>
                    </td>
                </tr>
            </table>
    {% endfor %}
    </div>
</div>

{% endblock %}

My current code is

axis=0

This gives me

[ [1,0],
  [0,0],
  [1,0] ]

I don't understand this error. What am I doing wrong and how can I get the average for all values greater than zero along # 1, 0, 1 filtered for > 0 gives 1, 1, average = (1+1)/2 = 1 # 0, 0, 0 filtered for > 0 gives 0, 0, 0, average = 0 [1 0] ? Thanks!

Answer 1

You can get the mask of greater than zeros and use it to do elementwise multilication and sum-reduction along the first axis. Finally, divide by the number of masked elements along the first axis for getting the average values.

Thus, one solution would be -

public abstract class Vehicle{}

public class Car extends Vehicle{}

public class Van extends Vehicle{}

Sample run -

<request>
  <car>...</car>
</request>

To account for all zero columns, it seems we are expecting <request> <vehicle xsi:type="car"></vehicle> </request> as the result. So, we can use mask = a > 0 # Input array : a out = np.einsum('i...,i...->...',a,mask)/mask.sum(0) to do the choosing, like so -

In [52]: a
Out[52]: 
array([[ 3, -3,  3],
       [ 2,  2,  0],
       [ 0, -3,  1],
       [ 0,  1,  1]])

In [53]: mask = a > 0

In [56]: np.einsum('i...,i...->...',a,mask) # summations of > 0s
Out[56]: array([5, 3, 5])

In [57]: np.einsum('i...,i...->...',a,mask)/mask.sum(0) # avg values of >0s
Out[57]: array([ 2.5       ,  1.5       ,  1.66666667])

Just ignore the warning there.

If you feel paranoid about warnings, use 0 -

np.where