How to get all children (ForeignKey based) from parent objects in a django template (e.g all comments for a blog post) ?
Article / CC BY-SA 4.0 / 02 mai 2022 / : 364 / Comments: None
Example of how to get all children from parent objects in a django template: [TOC] ### Models.py file Let's consider the following case: a blog website in which a post can be created and commented as well: class Blog_Post(models.Model): content = models.TextField() date_created = models.DateTimeField(default=datetime.now) class Blog_Post_Comment(models.Model): blog_post = models.ForeignKey(Blog_Post, null=True, blank=True, default = None,on_delete=models.DO_NOTHING) ...
How to append a new li to ul using javascript ?
Article / CC BY-SA 4.0 / 08 avril 2022 / : 94 / Comments: None
Examples of how to append a new li to ul using javascript: [TOC] ### Create a simple HTML page Let's consider the following html page: <!DOCTYPE html> <html lang="en" dir="ltr"> <head> <meta charset="utf-8"> <title></title> </head> <body> <ul id="mylist"> <li>item 1</li> <li>item 2</li> <li>item 3</li> </ul> <script> </script> </body> </html> The goal is to append 'item-4' to the ul with the id = "mylist" using javasc ...
How to fix "TypeError: Object of type datetime is not JSON serializable" in python ?
Article / CC BY-SA 4.0 / 04 avril 2022 / : 64 / Comments: None
Example of how to fix the TypeError: Object of type datetime is not JSON serializable" in python: [TOC] Let's consider an example: ### Create a datetime object Reminder: to create a datetime object in python import datetime x = datetime.datetime.now() gives for example 2022-04-04 14:16:59.604425 which is a datetime object ### Create a json file Now if we try to create a json file using a dictionary with a datetime object inside: import json dict = {"me ...
How to remove, drop a table in a database with the django web framework ?
Article / CC BY-SA 4.0 / 21 mars 2022 / : 56 / Comments: None
Example of how to drop a table in a database with django: [TOC] ### Start django database shell In the terminal go the the folder with the manage.py file and then enter the following command: python manage.py dbshell It is going to start a shell associated with the database type. For example with the default SQLite it will returns: SQLite version 3.35.4 2021-04-02 15:20:15 Enter ".help" for usage hints. sqlite> ### SQLite database #### Get all tables name To ge ...
How to get json data from a url using vanilla javascript only ?
Article / CC BY-SA 4.0 / 20 mars 2022 / : 1332 / Comments: None
Examples of how to get json data from a url using only vanilla javascript: [TOC] ### Video: tips For Using Async/Await in JavaScript I was looking for to remove JQuery and replace it by only vanilla javascript to increase the speed of my websites (in particular by replacing all ajax calls that retrieve json data from n url). Found a lot of documentations online (see references below) but the following youtube video by James Q. Quick summarized everything very well: [youtube_video_id: ...
How to create a string variable on multiple lines in javascript ?
Article / CC BY-SA 4.0 / 09 mars 2022 / : 50 / Comments: None
Examples of how to create a string variable on multiple lines in javascript [TOC] ### Example 1 To create a string variable on multiple lines in javascript, a solution is to use a [template literal](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals) which is delimited by backticks ``: var s = `an example of a very very very very very very very very very veryvery very long string` console.log( s ); ### Example 2 Another exampl ...
How to add text in a html page using javascript ?
Article / CC BY-SA 4.0 / 08 mars 2022 / : 65 / Comments: None
Examples of how to add text in a html page using javascript: [TOC] ### Add text using innerHTML <!DOCTYPE html> <html lang="en" dir="ltr"> <head> <meta charset="utf-8"> <title></title> </head> <body> <div id="intro"> <h1>Learning Javascript</h1> <p>First paragraph</p> </div> <script> document.querySelector("#intro").innerHTML += "<p>Second paragraph</p>"; </script> </body> </html> [images:learning-javascript-ad ...
How to check if a string contains another string (substring) in javascript ?
Article / CC BY-SA 4.0 / 04 mars 2022 / : 79 / Comments: None
Examples of how to test if a string contains another string (substring) in javascript: [TOC] ### Check if a string contains another string in javascript Let's consider the following string: var s = 'Tokyo is the most populated city in the world' To check for example if s contains the word 'city', a solution is to use [includes()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes): console.log( s.includes('city') ); returns he ...
How to convert a string representation of a number into a integer with javascript ?
Article / CC BY-SA 4.0 / 03 mars 2022 / : 63 / Comments: None
Examples of how to convert a string representation of a number into a integer with javascript : [TOC] ### Convert a string into an integer Let's consider the following variable var s = '42' The variable type can be checked using typeof console.log( typeof s ); gives here string To convert the above string into a integer, a solution is to use [parseInt()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt) var i = parseInt(s ...
How to create a date object in javascript for the current date or for a given year, month and day ?
Article / CC BY-SA 4.0 / 02 mars 2022 / : 74 / Comments: None
Examples of how to create a date object in javascript: [TOC] ### Create a date object in javascript for the current date To create a date object in javascript there is the [Date() constructor](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/Date). A simple utilisation of date() is to get the current date: var now = new Date(); console.log( now ); returns for example Wed Mar 02 2022 13:46:30 GMT-0500 (Eastern Standard Time) ### Cre ...
How to add an element to an array in javascript ?
Article / CC BY-SA 4.0 / 02 mars 2022 / : 107 / Comments: None
Examples of how to add an element to an array in javascript: [TOC] ### Add an element at the end of an array using push() Let's create a simple array: var A = [1,2,3,4]; console.log( A ); gives [1, 2, 3, 4] To append a new element at the end a solution is to use push(). An example, add the element 5 to the matrix A: A.push(5); console.log( A ); gives [1, 2, 3, 4, 5] var A = [1,2,3,4]; var B = [5,6]; A.push(B); console.log( A ); gives ...
How to loop over an array in javascript ?
Article / CC BY-SA 4.0 / 01 mars 2022 / : 78 / Comments: None
Examples of how to loop over each items of an array in javascript: [TOC] ### Create an array in javascript Let's create a very simple array in javascript var data = [9,5,7,3,1,4]; Note that we can test if it is an array using the following method: console.log( Array.isArray(data) ); which gives True here. To get the size of an array: console.log( data.length ); gives 6 And to get a given element by index: console.log( data[0] ); re ...
How to save the architecture of a tensorflow model (summary) in a json file ?
Article / CC BY-SA 4.0 / 23 février 2022 / : 140 / Comments: None
Example of how to show save the architecture of a tensorflow model (summary) in a json file: [TOC] ### Create a model Let's create a simple untrained model with TensorFlow: from keras.utils.data_utils import get_file from tensorflow import keras from tensorflow.keras import layers model = keras.Sequential([ layers.Dense(20, activation='relu', input_shape=[11]), layers.Dense(10, activation='relu'), layers.Dense(10, activation='relu'), ...
How to filter dataframe rows using a OR statement with pandas ?
Article / CC BY-SA 4.0 / 21 février 2022 / : 151 / Comments: None
Examples of how to filter dataframe rows using multiple conditions with OR in pandas: [TOC] ### Create a dataframe with pandas Let's first create a dataframe with pandas using a dictionary: import pandas as pd import numpy as np data= {'A':[-1,-2,3,4,5], 'B':[6,-7,8,9,-10], 'C':[11,12,13,14,15],} df = pd.DataFrame(data) returns here A B C 0 -1 6 11 1 -2 -7 12 2 3 8 13 3 4 9 14 4 5 - ...
How to check if a variable is a string in javascript ?
Article / CC BY-SA 4.0 / 15 février 2022 / : 200 / Comments: None
Examples of how to check if a variable is a string in javascript: [TOC] ### String variable Create a string var s = 'Hello world !' to check if it is a string a solution is to use typeof: console.log(typeof s === 'string'); gives here true Check if it is a string object: console.log(s instanceof String); gives false ### String object Create a string object var sobj = new String('Hello World !'); console.log(typeof sobj === 'string'); gi ...
How to convert a string object representation to a string in javascript ?
Article / CC BY-SA 4.0 / 15 février 2022 / : 172 / Comments: None
Examples of how to convert a string object representation to a string in javascript: [TOC] ### Create a string object To create a string object a solution is to use [String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String) let mystringobj = new String('Hello World !'); then if we test that mystringobj is a string console.log(typeof mystringobj === 'string'); it returns false However if we test if it is a instanceof String ...
How to create an array in javascript and get an element by index ?
Article / CC BY-SA 4.0 / 14 février 2022 / : 176 / Comments: None
Examples of how to create an array in javascript and get an element by index: [TOC] ### Create an array in javascript Examples of how to create arrays in javascript var data_1 = [1,2,3,4]; var data_2 = [1,['Ben','Tom','Jess'],3,4]; var data_3 = [[1,2],[3,4],[5,6]]; ### Get array length To get array's length: data_1.length; gives 4 For the second array data_2.length; gives 4 and the the third array: data_2.length; gives 3 ### Ch ...
How to check if a javascript variable is an array ?
Article / CC BY-SA 4.0 / 14 février 2022 / : 166 / Comments: None
Example of how to check if a javascript variable is an array: [TOC] ### Using Array.isArray() A solution to check if a javascript variable is an array is to use [Array.isArray()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/isArray) var data = [1,2,3,4]; Array.isArray(data); returns here true while data = 3; returns False #### With a if statement var data = [1,2,3,4]; if (!Array.isArray(data)) { console.l ...
Pour ajouter une image dans une note il faut utiliser la balise suivante:
[image: size: caption:]
ou image est l'adresse url de l'image, size (optionnel) la taille entre 10 et 100% de la largeur de la page, et caption (optionnel) la légende.
On peut aussi ajouter plusieurs images. Exemple de comment ajouter 4 images dans un tableau 2*2:
[images:image_1;image_2;image_3;image_4 dim:2*2 size:100 caption:]
On peu ajouter un lien comme ceci:
[title](url)
exemple avec un lien externe article de wikipedia:
[article de wikipedia](https://fr.wikipedia.org/wiki/Math%C3%A9matiques)exemple avec un lien interne Link
[Link](/Articles/Comment-simplifier-une-fraction-Mathématiques/))Exemple de comment créer des sections:
# section 1 ## section 1.2 ## section 1.3 ### section 1.3.1 # section 2
et ajouter une table des matières:
[TOC]
Exemple de comment créer un tableau à deux colonnes
Titre 1 | Titre 2 ------------- | ------------- text | text text | text
| header | header |
|---|---|
| text | text |
| text | text |
Exemple de comment créer un tableau à trois colonnes
Titre 1 | Titre 2 | Titre 3 ------------- | ------------- | ------------- text | text | text text | text | text
| header | header | header |
|---|---|---|
| text | text | text |
| text | text | text |
Attribution-ShareAlike 4.0 International License.
Attribution 4.0 International License.
CC0 1.0 Universal Public Domain Dedication
This work is free of known copyright restrictions.
Attribution-ShareAlike 4.0 International License.
Attribution 4.0 International License.
CC0 1.0 Universal Public Domain Dedication
This work is free of known copyright restrictions.
