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Drawing an image from a data URL to a canvas
... Canvas Context lets you copy all or a portion of an image (or canvas, or video) onto a canvas.
You might use it like so:
var myCanvas = document.getElementById('my_canvas_id');
var ctx = myCanvas.getContext('2d');
var img = new Image;
img.onload = function(){
ctx.drawImage(img,0,0); // Or at wh...
Managing relationships in Laravel, adhering to the repository pattern
... your "business problem".
A Course is a "entity", with attributes (title, id, etc) and even other entities (Assignments, which have their own attributes and possibly entities).
Your "Course" repository should be able to return a Course and the Courses' attributes/Assignments (including Assignment)...
What is the difference between “INNER JOIN” and “OUTER JOIN”?
...ally show any distinction between different types of join predicate or provide a framework for reasoning about how they will operate.
There is no substitute for understanding the logical processing and it is relatively straightforward to grasp anyway.
Imagine a cross join.
Evaluate the on clause ag...
Remove duplicated rows
...moval, either from specific columns/variables (as in this question) or considering all columns/variables. dplyr is part of the tidyverse.
Data and package
library(dplyr)
dat <- data.frame(a = rep(c(1,2),4), b = rep(LETTERS[1:4],2))
Remove rows duplicated in a specific column (e.g., columna)
...
What happens if you call erase() on a map element while iterating from begin to end?
...;
while(pm_it != port_map.end())
{
if (pm_it->second == delete_this_id)
{
pm_it = port_map.erase(pm_it);
}
else
{
++pm_it;
}
}
C++03
Erasing elements in a map does not invalidate any iterators.
(apart from iterators on the element that was deleted)
Actu...
What's an elegant way to conditionally add a class to an HTML element in a view?
...usually you should represent success with boolean true or a numeric record ID, and failure with boolean false or nil. This way you can just test your variable:
<div class="<%= 'ok' if @success %>">
A second form using the ternary ?: operator is useful if you want to choose between tw...
delete_all vs destroy_all?
...ach to delete records from a table. For instance, I have a user whose user ID is across many tables. I want to delete this user and every record that has his ID in all tables.
...
How do I clear this setInterval inside a function?
...igger(markers[timedCount], "click");
timedCount++;
}, 5000 );
};
var id = intervalTrigger();
Then to clear the interval:
window.clearInterval(id);
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What is the difference between JOIN and JOIN FETCH when using JPA and Hibernate
...
I use native query with Lazy fetch in both sides of relationship but still loads hierarchy of child relations.
– Badamchi
Dec 25 '19 at 12:18
...
Rails server says port already used, how to kill that process?
...s what webrick normally uses), type this in your terminal to find out the PID of the process:
$ lsof -wni tcp:3000
Then, use the number in the PID column to kill the process:
$ kill -9 PID
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