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What is the correct way of using C++11's range-based for?
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This is inefficient code, e.g., if these elements are instances of std::string,
heap memory allocations can be done, with expensive trips to the memory manager, etc.
This is useless if we just want to observe the elements in a container.
So, a better syntax is available: capture by const referen...
How to get key names from JSON using jq
... cat input.json | jq -r 'keys'
From jq help:
-r output raw strings, not JSON texts;
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How to use concerns in Rails 4
...tags, through: :taggings
class_attribute :tag_limit
end
def tags_string
tags.map(&:name).join(', ')
end
def tags_string=(tag_string)
tag_names = tag_string.to_s.split(', ')
tag_names.each do |tag_name|
tags.build(name: tag_name)
end
end
# methods define...
Change type of varchar field to integer: “cannot be cast automatically to type integer”
...y this, it will work for sure.
When writing Rails migrations to convert a string column to an integer you'd usually say:
change_column :table_name, :column_name, :integer
However, PostgreSQL will complain:
PG::DatatypeMismatch: ERROR: column "column_name" cannot be cast automatically to type i...
How to make an element in XML schema optional?
...
Try this
<xs:element name="description" type="xs:string" minOccurs="0" maxOccurs="1" />
if you want 0 or 1 "description" elements, Or
<xs:element name="description" type="xs:string" minOccurs="0" maxOccurs="unbounded" />
if you want 0 to infinity number of "de...
Set focus on TextBox in WPF from view model
...odel(exampleViewModel.cs):write the following
Messenger.Default.Send<string>("focus", "DoFocus");
now in your View.cs(not the XAML the view.xaml.cs) write the following in the constructor
public MyView()
{
InitializeComponent();
Messenger.Default.Registe...
EditText maxLines not working - user can still input more lines than set
...eyEvent.ACTION_UP) {
// get EditText text
String text = ((EditText) v).getText().toString();
// find how many rows it cointains
int editTextRowCount = text.split("\\n").length;
// user has input more than limited - le...
What is 'YTowOnt9'?
...k sometimes renders hidden inputs with value YTowOnt9 . I can't find that string anywhere in the (huge) codebase, and can't figure out where it came from. I decided to Google for that particular string, and the result surprised me. Over half a million - kind of random - hits. I haven't found any ...
Should URL be case sensitive?
...sitive or not.
Take this page for example, stackoverflow.com receives GET string /questions/7996919/should-url-be-case-sensitive, sending a HTML document to your browser. Stackoverflow.com is case insensitive because it produces the same result for /QUEStions/7996919/Should-url-be-case-sensitive.
...
Is the LIKE operator case-sensitive with MSSQL Server?
...objects.
It is also possible to change a column collation on the fly for string comparison, but this is highly unrecommended in a production environment because it is extremely costly.
select
column1 collate sql_latin1_general_cp1_ci_as as column1
from table1
...