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Why do C++ libraries and frameworks never use smart pointers?
...<typename T>
struct Pointer {
#ifdef <Cpp11>
typedef std::unique_ptr<T> type;
#else
typedef T* type;
#endif
};
And in your code use it as:
Pointer<int>::type p;
For those who say that a smart pointer and a raw pointer are different, I agree with that. The code above ...
Validate uniqueness of multiple columns
...r, one should add a unique constraint to db table. You can set it with add_index helper for one (or multiple) field(s) by running the following migration:
class AddUniqueConstraints < ActiveRecord::Migration
def change
add_index :table_name, [:field1, ... , :fieldn], unique: true
end
end
...
An efficient way to transpose a file in Bash
...dline
COLS=${#line[@]} # save number of columns
index=0
while read -a line ; do
for (( COUNTER=0; COUNTER<${#line[@]}; COUNTER++ )); do
array[$index]=${line[$COUNTER]}
((index++))
done
done < "$1"
for (( ROW = 0; ROW < COLS; ROW++ )); do
...
Python constructors and __init__
...e new method, rendering the first method inaccessible.
As to your general question about constructors, Wikipedia is a good starting point. For Python-specific stuff, I highly recommend the Python docs.
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NOT IN vs NOT EXISTS
... explained here. It is all there to convert the previous single correlated index seek on Sales.SalesOrderDetail.ProductID = <correlated_product_id> to two seeks per outer row. The additional one is on WHERE Sales.SalesOrderDetail.ProductID IS NULL.
As this is under an anti semi join if that ...
Rails: How to get the model class name based on the controller class name?
...will do it:
class HouseBuyersController < ApplicationController
def index
@model_name = controller_name.classify
end
end
This is often needed when abstracting controller actions:
class HouseBuyersController < ApplicationController
def index
# Equivalent of @house_buyers = ...
What is the difference between CascadeType.REMOVE and orphanRemoval in JPA?
... answered Nov 6 '18 at 11:52
Mr.QMr.Q
2,93933 gold badges3030 silver badges3434 bronze badges
...
Specifying and saving a figure with exact size in pixels
...at large, so you won't be able to show a figure of that size (matplotlib requires the figure to fit in the screen, if you ask for a size too large it will shrink to the screen size). Let's imagine you want an 800x800 pixel image just for an example. Here's how to show an 800x800 pixel image in my mo...
Is an array name a pointer?
...as arr[1] */
/* arr not used as value */
size_t bytes = sizeof arr;
void *q = &arr; /* void pointers are compatible with pointers to any object */
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Loop through properties in JavaScript object with Lodash
...ello",
[Symbol.iterator]: function() {
const thisObj = this;
let index = 0;
return {
next() {
let keys = Object.keys(thisObj);
return {
value: thisObj[keys[index++]],
done: (index > keys.length)
};
}
};
}
};
Now we can ...