You can revert back by migrating to the previous migration. See the migrations folder of your app and then see all the migrations

Say for an example, if your migrations are something like below ordered number wise and latest migration 0012_latest_migration is applied currently.

    0010_previous_migration
    0011_next_migration
    0012_latest_migration

And You want to go back to  0010_previous_migration

    ./manage.py migrate my_app 0010_previous_migration 

and then you can delete all migrations after that like here delete both 0011_next_migration and 0012_latest_migration as you already applied   0010_previous_migration.

If you&#39;re using Django 1.8+, you can show the names of all the migrations with

    ./manage.py showmigrations my_app

To reverse all migrations for an app to initial or start, you can run:

    ./manage.py migrate my_app zero

React-navigation docs are still young, and reading through the issues is not working quite much for me (changes on each version) does anyone have a working method to center title in Android using `react-navigation` in React Native?

How can we center title of react-navigation header?

Within a Vuex store mutation, is it possible to access a getter? Consider the below example.

    new Vuex.Store({
        state: {
            question: &#39;Is it possible to access getters within a Vuex mutation?&#39;
        },
        mutations: {
            askQuestion(state) {
                // TODO: Get question from getter here
                let question = &#39;&#39;;
                
                if (question) {
                	// ...
                }
            }
        },
        getters: {
            getQuestion: (state) =&gt; {
                return state.question;
            }
        }
    });

Of course the example doesn&#39;t make much sense, because I could just access the `question` property directly on the `state` object within the mutation, but I hope you see what I am trying to do. That is, conditionally manipulating state.

Within the mutation, `this` is `undefined` and the `state` parameter gives access to the `state` object, and not the rest of the store.

[The documentation on mutations][1] doesn&#39;t mention anything about doing this.

My guess would be that it&#39;s not possible, unless I missed something? I guess the alternative would be to either perform this logic outside of the store (resulting in code duplication) or implementing an action that does this, because actions have access to the entire store context. I&#39;m pretty sure that it&#39;s a better approach, that is to keep the mutation focused on what it&#39;s actually supposed to do; mutate the state. That&#39;s probably what I&#39;ll end up doing, but I&#39;m just curious if accessing a getter within a mutation is even possible?


  [1]: http://vuex.vuejs.org/en/mutations.html

Accessing getters within Vuex mutations

Actually, what I do is: 

 - Delete the migration file.
 - Delete the row from the table of django_migrations on the database.
 - Delete the changes applied by the migration that I want to delete or unapplied.

I want to know if there&#39;s another way to do this.

Is there a way to undo a migration on Django and uncheck it from the list of showmigrations?

<p>Actually, what I do is:</p>
<ul>
<li>Delete the migration file.</li>
<li>Delete the row from the table of django_migrations on the database.</li>
<li>Delete the changes applied by the migration that I want to delete or unapplied.</li>
</ul>
<p>I want to know if there's another way to do this.</p>


When I stop the script manually in PyCharm, process finished with exit code 137. But I didn&#39;t stop the script. Still got the exit code 137. What&#39;s the problem?

Python version is 3.6, process finished when running xgboost.train() method.

Process finished with exit code 137 in PyCharm

I am using a **LocalExecutor** and my dag has **3 tasks** where task(C) is dependant on task(A). Task(B) and task(A) can run in parallel something like below

A--&gt;C

B

**So task(A) has failed** and but **task(B) ran fine**. Task(C) is yet to run as task(A) has failed.

My question is **how do i re run Task(A) alone so Task(C) runs** once Task(A) completes and Airflow UI marks them as success.



How to restart a failed task on Airflow

I want to run Python code in Microsoft Visual Studio Code but it gives an error:

&gt; Linter pylint is not installed

I installed:

* The Visual Studio Code Python extension
* Python&amp;nbsp;3
* Anaconda

How can I install Pylint?





Error message &quot;Linter pylint is not installed&quot;

I&#39;m launching a number of subprocesses with subprocess.Popen in Python.
I&#39;d like to check whether one such process has completed. I&#39;ve found two ways of checking the status of a subprocess, but both seem to force the process to complete.
One is using process.communicate() and printing the returncode, as explained [here][1].
Another is simply calling process.wait() and checking that it returns 0.

Is there a way to check if a process is still running without waiting for it to complete if it is?

  [1]: https://stackoverflow.com/questions/14043030/checking-status-of-process-with-subprocess-popen-in-python

Is there a way to check if a subprocess is still running?

I have this list:

    colors = [&quot;R&quot;, &quot;G&quot;, &quot;B&quot;, &quot;Y&quot;]

and I want to get 4 random letters from it, but including repetition.

Running this will only give me 4 unique letters, but never any repeating letters:

    print(random.sample(colors,4))

How do I get a list of 4 colors, with repeating letters possible?


Get a random sample with replacement

I have a deprecation warning in Django 1.11:

    RemovedInDjango20Warning: Passing a 3-tuple to django.conf.urls.include() is deprecated. Pass a 2-tuple containing the list of patterns and app_name, and provide the namespace argument to include() instead.
      url(r&#39;^admin/&#39;, include(admin.site.urls))

In Django 2.0 this gives the error:

    django.core.exceptions.ImproperlyConfigured: Passing a 3-tuple to include() is not supported. 
    Pass a 2-tuple containing the list of patterns and app_name, and provide the namespace argument to include() instead.

How should I change `url(r&#39;^admin/&#39;, include(admin.site.urls))`? I tried to look at the documentation, but I have no clue ...

Here is my urls.py:

    from django.conf.urls import include, url
    from django.contrib import admin
    admin.autodiscover()
    
    urlpatterns = [
        url(r&#39;^admin/&#39;, include(admin.site.urls)),
        url(r&#39;^admin/django-ses/&#39;, include(&#39;django_ses.urls&#39;)),
        url(r&#39;^api/1.0/&#39;, include(&#39;feedcrunch_api_v1.urls&#39;)),
        url(r&#39;^oauth/&#39;, include(&#39;oauth.urls&#39;)),
        url(r&#39;^@(?P&lt;feedname&gt;\w+)/admin/&#39;, include(&#39;feedcrunch_rssadmin.urls&#39;)),
        url(r&#39;^@(?P&lt;feedname&gt;\w+)/&#39;, include(&#39;feedcrunch_rssviewer.urls&#39;)),
        url(r&#39;^api-auth/&#39;, include(&#39;rest_framework.urls&#39;, namespace=&#39;rest_framework&#39;)),
        url(r&#39;&#39;, include(&#39;feedcrunch_home.urls&#39;)),
    ]



Django Deprecation Warning or ImproperlyConfigured error - Passing a 3-tuple to django.conf.urls.include() is not supported

I am trying to make a very simple `Subquery` that uses `OuterRef` (not for practical purposes, but just to get it working), but I keep running into the same error.

`posts/models.py` code


    from django.db import models

    class Tag(models.Model):
        name = models.CharField(max_length=120)
        def __str__(self):
            return self.name

    class Post(models.Model):
        title = models.CharField(max_length=120)
        tags = models.ManyToManyField(Tag)
        def __str__(self):
            return self.title

`manage.py shell` code

    &gt;&gt;&gt; from django.db.models import OuterRef, Subquery
    &gt;&gt;&gt; from posts.models import Tag, Post
    &gt;&gt;&gt; tag1 = Tag.objects.create(name=&#39;tag1&#39;)
    &gt;&gt;&gt; post1 = Post.objects.create(title=&#39;post1&#39;)
    &gt;&gt;&gt; post1.tags.add(tag1)
    &gt;&gt;&gt; Tag.objects.filter(post=post1.pk)
    &lt;QuerySet [&lt;Tag: tag1&gt;]&gt;
    &gt;&gt;&gt; tags_list = Tag.objects.filter(post=OuterRef(&#39;pk&#39;))
    &gt;&gt;&gt; Post.objects.annotate(count=Subquery(tags_list.count()))

The last two lines should give me number of tags for each Post object. And here I keep getting the same error:

    ValueError: This queryset contains a reference to an outer query and may only be used in a subquery.

Simple Subquery with OuterRef

Just received the Sentry error `TypeError context must be a dict rather than Context.` on one of my forms.  I know it has something to do with Django 1.11, but I am not sure what to change to fix it.

**Offending line**

`message = get_template(&#39;email_forms/direct_donation_form_email.html&#39;).render(Context(ctx))`

**Entire View**

    def donation_application(request):
        if request.method == &#39;POST&#39;:
            form = DirectDonationForm(data=request.POST)
            if form.is_valid():
                stripe.api_key = settings.STRIPE_SECRET_KEY
                name = request.POST.get(&#39;name&#39;, &#39;&#39;)
                address = request.POST.get(&#39;address&#39;, &#39;&#39;)
                city = request.POST.get(&#39;city&#39;, &#39;&#39;)
                state = request.POST.get(&#39;state&#39;, &#39;&#39;)
                zip = request.POST.get(&#39;zip&#39;, &#39;&#39;)
                phone_number = request.POST.get(&#39;phone_number&#39;, &#39;&#39;)
                support = request.POST.get(&#39;support&#39;, &#39;&#39;)
                agree = request.POST.get(&#39;agree&#39;, &#39;&#39;)
                email_address = request.POST.get(&#39;email_address&#39;, &#39;&#39;)
                number = request.POST.get(&#39;number&#39;, &#39;&#39;)
                cvc = request.POST.get(&#39;cvc&#39;, &#39;&#39;)
                exp = request.POST.get(&#39;exp&#39;, &#39;&#39;)
                # token = form.cleaned_data[&#39;stripe_token&#39;],
                # exp_m = int(request.POST.get(&#39;exp_month&#39;, &#39;&#39;))
                # exp_y = int(request.POST.get(&#39;exp_year&#39;, &#39;&#39;))
    
                exp_month = exp[0:2]
                exp_year = exp[5:9]
    
                subject = &#39;New Donation&#39;
                from_email = settings.DEFAULT_FROM_EMAIL
                recipient_list = [&#39;deniselarkins@/////\\\\\.com&#39;,
                                  &#39;charles@/////\\\\\.net&#39;,
                                  &#39;marcmunic@/////\\\\\.com&#39;,
                                  ]
    
                token = stripe.Token.create(
                    card={
                        &#39;number&#39;: number,
                        &#39;exp_month&#39;: exp_month,
                        &#39;exp_year&#39;: exp_year,
                        &#39;cvc&#39;: cvc
                    },
                )
    
                customer = stripe.Customer.create(
                    email=email_address,
                    source=token,
                )
    
                total_support = decimal.Decimal(support) / 100
                total_charge = decimal.Decimal(int(support)) / 100
    
                # Charge the user&#39;s card:
                charge = stripe.Charge.create(
                    amount=total_charge,
                    currency=&#39;usd&#39;,
                    description=&#39;Donation&#39;,
                    customer=customer.id
                )
    
                ctx = {
                    &#39;name&#39;: name,
                    &#39;address&#39;: address,
                    &#39;city&#39;: city,
                    &#39;state&#39;: state,
                    &#39;zip&#39;: zip,
                    &#39;phone_number&#39;: phone_number,
                    &#39;email_address&#39;: email_address,
                    &#39;agree&#39;: agree,
                    &#39;charge&#39;: charge,
                    &#39;customer&#39;: customer,
                    &#39;total_support&#39;: total_support,
                    &#39;total_charge&#39;: total_charge
                }
    
                message = get_template(&#39;email_forms/direct_donation_form_email.html&#39;).render(Context(ctx))
                msg = EmailMessage(subject, message, from_email=from_email, to=recipient_list)
                msg.content_subtype = &#39;html&#39;
                msg.send(fail_silently=True)
    
                return redirect(
                    &#39;/contribute/donation-support-thank-you/?name=&#39; + name +
                    &#39;&amp;address=&#39; + address +
                    &#39;&amp;state=&#39; + state +
                    &#39;&amp;city=&#39; + city +
                    &#39;&amp;zip=&#39; + zip +
                    &#39;&amp;phone_number=&#39; + phone_number +
                    &#39;&amp;email_address=&#39; + email_address +
                    &#39;&amp;total_support=&#39; + str(total_support) +
                    &#39;&amp;total_charge=&#39; + str(total_charge)
                )
        context = {
            &#39;title&#39;: &#39;Donation Pledge&#39;,
        }
    
        return render(request, &#39;contribute/_donation-application.html&#39;, context)

Django 1.11 TypeError context must be a dict rather than Context

I use community pycharm and the version of python is 3.6.1, django is 1.11.1. This warning has no affect on running, but I cannot use the IDE&#39;s auto complete.

Unresolved attribute reference &#39;objects&#39; for class &#39;&#39; in PyCharm

I have a Python/Django proyect. Due to some rolls back, and other mixed stuff we ended up in a kind of odd scenario.

The current scenario is like this:

- DB has the correct tables
- DB can&#39;t be rolled back or dropped
- Code is up to date

- Migrations folder is ***behind*** the DB by one or two migrations. (These migrations were applied from somewhere else and that &quot;somewhere else&quot; doesn&#39;t exist anymore)

- I add and alter some models
- I run *makemigrations*
- New migrations are created, but it&#39;s a mix of new tables and some tables that already exist in the DB.
- If I run *migrate* it will complain that some of the tables that I&#39;m trying to create already exist.


What I need:


To be able to run the migrations and kind of &quot;ignore&quot; the existing tables and apply the new ones. Or any alternative way to achieve this.

Is that possible?

How to force migrations to a DB if some tables already exist in Django?

When I try running the command &quot;update-database&quot;, I get this exception:

&gt; Specify the &#39;-Verbose&#39; flag to view the SQL statements being applied
&gt; to the target database.     System.IO.FileNotFoundException: Could not
&gt; load file or assembly &#39;Microsoft.Build.Framework, Version=15.1.0.0,
&gt; Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&#39; or one of its
&gt; dependencies. The system cannot find the file specified. File name:
&gt; &#39;Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral,
&gt; PublicKeyToken=b03f5f7f11d50a3a&#39;    
&gt; 
&gt; WRN: Assembly binding logging is turned OFF. To enable assembly bind
&gt; failure logging, set the registry value
&gt; [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There
&gt; is some performance penalty associated with assembly bind failure
&gt; logging. To turn this feature off, remove the registry value
&gt; [HKLM\Software\Microsoft\Fusion!EnableLog].
&gt; 
&gt; Could not load file or assembly &#39;Microsoft.Build.Framework,
&gt; Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&#39; or
&gt; one of its dependencies. The system cannot find the file specified.`

Could not load file or assembly &#39;Microsoft.Build.Framework&#39;(VS 2017)

Hi read all the included documentation here in https://laravel.com/docs/5.4/migrations.

Is there a way on how to migrate a certain migration file (1 migration only), cause right now every time there is a change I use `php artisan migrate:refresh` and all fields are getting reset.


Laravel Migrate Specific File(s) from Migrations

As Angular 6 is here, I want to upgrade or move my angular 5 client application to angular 6, but I&#39;m not getting any tutorial or anything which can guide me through. 

According to me I just need to run a new Angular CLI and then have to move my older source to new project. I read the Angular 6 is using a new renderer called Ivy. Will I have to change my project according to Ivy?

Want to upgrade project from Angular v5 to Angular v6

After migrating application from angular 5 to 6, on running ng serve the following errors pop up.

&gt; Schema validation failed with the following errors:
  Data path &quot;&quot; should NOT have additional properties(project).
Error: Schema validation failed with the following errors:
  Data path &quot;&quot; should NOT have additional properties(project).
    at MergeMapSubscriber._registry.compile.pipe.operators_1.concatMap.validatorResult [as project] (.../TemplateApp/me-cmf-web-template-angular/node_modules/@angular-devkit/core/src/workspace/workspace.js:210:42)
    at MergeMapSubscriber._tryNext (/.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/operators/mergeMap.js:65:27)
    at MergeMapSubscriber._next (.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/operators/mergeMap.js:55:18)
    at MergeMapSubscriber.Subscriber.next (/home/training/Attinad_Projects/TemplateApp/me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/Subscriber.js:64:18)
    at MergeMapSubscriber.notifyNext (.../TemplateApp/me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/operators/mergeMap.js:84:26)
    at InnerSubscriber._next (.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/InnerSubscriber.js:25:21)
    at InnerSubscriber.Subscriber.next (/.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/Subscriber.js:64:18)
    at MapSubscriber._next (.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/operators/map.js:52:26)
    at MapSubscriber.Subscriber.next (/.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/Subscriber.js:64:18)
    at SwitchMapSubscriber.notifyNext (.../me-cmf-web-template-angular/node_modules/@angular-devkit/core/node_modules/rxjs/internal/operators/switchMap.js:77:26)

 

I assume that the error is with .angular.json file which I re-named from .angular-cli.json . 

My .angular.json file is as follows : 



    {
        &quot;$schema&quot;: &quot;./node_modules/@angular/cli/lib/config/schema.json&quot;,
        &quot;project&quot;: {
            &quot;name&quot;: &quot;mediaweb&quot;
        },
        &quot;apps&quot;: [{
                &quot;root&quot;: &quot;src&quot;,
                &quot;outDir&quot;: &quot;dist/browser&quot;,
                &quot;assets&quot;: [
                    &quot;assets&quot;,
                    &quot;favicon.ico&quot;
                ],
                &quot;index&quot;: &quot;index.html&quot;,
                &quot;main&quot;: &quot;main.ts&quot;,
                &quot;polyfills&quot;: &quot;polyfills.ts&quot;,
                &quot;test&quot;: &quot;test.ts&quot;,
                &quot;tsconfig&quot;: &quot;tsconfig.app.json&quot;,
                &quot;testTsconfig&quot;: &quot;tsconfig.spec.json&quot;,
                &quot;prefix&quot;: &quot;app&quot;,
                &quot;styles&quot;: [
                    &quot;styles.scss&quot;,
                    &quot;../node_modules/owl.carousel/dist/assets/owl.carousel.css&quot;,
                    &quot;../node_modules/owl.carousel/dist/assets/owl.theme.default.css&quot;,
                    &quot;../node_modules/video.js/dist/video-js.css&quot;
                ],
                &quot;scripts&quot;: [
                    &quot;../node_modules/jquery/dist/jquery.js&quot;,
                    &quot;../node_modules/owl.carousel/dist/owl.carousel.js&quot;,
                    &quot;../node_modules/video.js/dist/ie8/videojs-ie8.js&quot;,
                    &quot;../node_modules/video.js/dist/video.js&quot;
                ],
                &quot;environmentSource&quot;: &quot;environments/environment.ts&quot;,
                &quot;environments&quot;: {
                    &quot;dev&quot;: &quot;environments/environment.dev.ts&quot;,
                    &quot;prod&quot;: &quot;environments/environment.prod.ts&quot;
                }
            },
            {
                &quot;platform&quot;: &quot;server&quot;,
                &quot;root&quot;: &quot;src&quot;,
                &quot;outDir&quot;: &quot;dist/server&quot;,
                &quot;assets&quot;: [
                    &quot;assets&quot;,
                    &quot;favicon.ico&quot;
                ],
                &quot;index&quot;: &quot;index.html&quot;,
                &quot;main&quot;: &quot;main.server.ts&quot;,
                &quot;test&quot;: &quot;test.ts&quot;,
                &quot;tsconfig&quot;: &quot;tsconfig.server.json&quot;,
                &quot;testTsconfig&quot;: &quot;tsconfig.spec.json&quot;,
                &quot;prefix&quot;: &quot;app&quot;,
                &quot;styles&quot;: [
                    &quot;styles.scss&quot;
                ],
                &quot;scripts&quot;: [],
                &quot;environmentSource&quot;: &quot;environments/environment.ts&quot;,
                &quot;environments&quot;: {
                    &quot;dev&quot;: &quot;environments/environment.dev.ts&quot;,
                    &quot;prod&quot;: &quot;environments/environment.prod.ts&quot;
                }
            }
        ],
        &quot;e2e&quot;: {
            &quot;protractor&quot;: {
                &quot;config&quot;: &quot;./protractor.conf.js&quot;
            }
        },
        &quot;lint&quot;: [{
                &quot;project&quot;: &quot;src/tsconfig.app.json&quot;,
                &quot;exclude&quot;: [&quot;**/node_modules/**&quot;, &quot;**/UI/**&quot;]
            },
            {
                &quot;project&quot;: &quot;src/tsconfig.spec.json&quot;,
                &quot;exclude&quot;: &quot;**/node_modules/**&quot;
            },
            {
                &quot;project&quot;: &quot;e2e/tsconfig.e2e.json&quot;,
                &quot;exclude&quot;: &quot;**/node_modules/**&quot;
            }
        ],
        &quot;test&quot;: {
            &quot;karma&quot;: {
                &quot;config&quot;: &quot;./karma.conf.js&quot;
            }
        },
        &quot;defaults&quot;: {
            &quot;styleExt&quot;: &quot;scss&quot;,
            &quot;component&quot;: {}
        }
    }

Should I re-structure the json file, if so how?.

Any help would be great.




Error: Schema validation failed with the following errors: Data path &quot;&quot; should NOT have additional properties(project)

We are planning to migrate our Java 8 project to use Java 11. But I noticed that Java 11 doesn&#39;t have a JRE folder.

In Java 9 and Java 10, folder structures are changed i.e. `java\jdk1.x` or `java\jre1.x`, where `x` is Java 9 or 10.

But in Java 11, I am getting only one folder, i.e. `java\jdk-11`. How will my client use my application without *jre*?

What I understood is that Java 11 is enforcing to modularize our application, and using jlink is needed to create our own jre to run the application in client.

Is my understanding correct?




Content Type	Original Author	Original Content on Stackoverflow
Question	César Villaseñor	View Question on Stackoverflow
Solution 1 - Python	Astik Anand	View Answer on Stackoverflow

Is there a way to undo a migration on Django and uncheck it from the list of showmigrations?

Python Problem Overview

Python Solutions

Solution 1 - Python

Accessing getters within Vuex mutations

How can we center title of react-navigation header?

Attributions