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How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
What differences, if any, between C++03 and C++11 can be detected at run-time?
...led with a C++ compiler, will return 1 (the trivial sulution with
#ifdef __cplusplus is not interesting).
8 Answers
...
How do I move files in node.js?
...e rename function to do that.
http://nodejs.org/docs/latest/api/fs.html#fs_fs_rename_oldpath_newpath_callback
fs.rename(oldPath, newPath, callback)
Added in: v0.0.2
oldPath <String> | <Buffer>
newPath <String> | <Buffer>
callback <Function>
Asynchronous...
How do I use WebRequest to access an SSL encrypted site using https?
...ValidationCallback <- Security.RemoteCertificateValidationCallback (fun _ _ _ _ -> true)
– David Grenier
Jan 10 '12 at 21:25
...
What does Ruby have that Python doesn't, and vice versa?
...ound as an object, and overwrite it:
def func(): print "hello"
def another_func(f): f()
another_func(func)
def func2(): print "goodbye"
func = func2
This is a fundamental feature of modern scripting languages. JavaScript and Lua do this, too. Ruby doesn't treat functions this way; naming a fun...
Read entire file in Scala?
...rt into any file which requires file manipulation:
import scala.io.Source._
With this, you can now do:
val lines = fromFile("file.txt").getLines
I would be wary of reading an entire file into a single String. It's a very bad habit, one which will bite you sooner and harder than you think. Th...
Extracting just Month and Year separately from Pandas Datetime column
...
the best answer is clearly.. df['mnth_yr'] = df.date_column.dt.to_period('M') as below from @jaknap32
– ihightower
Jun 23 '17 at 6:16
1
...
Natural Sort Order in C#
...omComparer<T> : IComparer<T> {
private Comparison<T> _comparison;
public CustomComparer(Comparison<T> comparison) {
_comparison = comparison;
}
public int Compare(T x, T y) {
return _comparison(x, y);
}
}
Example:
string[] files = Dire...
How to debug JavaScript / jQuery event bindings with Firebug or similar tools?
...Query stores your handler internally).
jQuery 1.8.x
var clickEvents = $._data($('#foo')[0], "events").click;
jQuery.each(clickEvents, function(key, handlerObj) {
console.log(handlerObj.handler) // prints "function() { console.log('clicked!') }"
})
...
Getting multiple keys of specified value of a generic Dictionary?
...e, perhaps maintain two dictionary mapping key->value and value->List_of_keys. If you do the latter you will trade storage for look up speed. It wouldn't take much to turn @Cybis example into such a data structure.
s...