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Rails DB Migration - How To Drop a Table?
... ActiveRecord::Migration
def change
drop_table :users do |t|
t.string :email, null: false
t.timestamps null: false
end
end
end
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Cloning an Object in Node.js
...
Possibility 1
Low-frills deep copy:
var obj2 = JSON.parse(JSON.stringify(obj1));
Possibility 2 (deprecated)
Attention: This solution is now marked as deprecated in the documentation of Node.js:
The util._extend() method was never intended to be used outside of internal Node.js modules....
MySQL check if a table exists without throwing an exception
...on table_exist($table){
global $con;
$table = $con->real_escape_string($table);
$sql = "show tables like '".$table."'";
$res = $con->query($sql);
return ($res->num_rows > 0);
}
Hope it helps.
Warning: as sugested by @jcaron this function could be vulnerable to sqli...
What is the purpose of double curly braces in React's JSX syntax?
...{rawMarkup}? Is it because the object {__html: rawMarkup} is mutable and a string isn't?
– Brian Kung
Mar 1 '15 at 21:02
2
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Can you explain the concept of streams?
...der : StreamReader {
private Random random = new Random();
public String ReadLine() { return random.Next().ToString(); }
}
// and to call it:
int x = ReadInt(new RandomNumbersStreamReader());
See? As long as your method doesn't care what the input source is, you can customize your source...
Simple explanation of clojure protocols
...ding Ruby. I suppose that ability to (re)define methods of any class (e.g. String, Fixnum) in Ruby is analogy to Clojure's defprotocol.
– defhlt
Jun 4 '13 at 21:37
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How do I convert seconds to hours, minutes and seconds?
...perations:
m, s = divmod(seconds, 60)
h, m = divmod(m, 60)
And then use string formatting to convert the result into your desired output:
print('{:d}:{:02d}:{:02d}'.format(h, m, s)) # Python 3
print(f'{h:d}:{m:02d}:{s:02d}') # Python 3.6+
...
Display a tooltip over a button using Windows Forms
... in this.Controls)
{
if (ctrl is Button && ctrl.Tag is string)
{
ctrl.MouseHover += new EventHandler(delegate(Object o, EventArgs a)
{
var btn = (Control)o;
ToolTip1.SetToolTip(btn, btn.Tag.ToString());
}...
Web scraping with Python [closed]
...', {'class': 'spad'})[0].tbody('tr'):
tds = row('td')
print tds[0].string, tds[1].string
# will print date and sunrise
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set gvim font in .vimrc file
...m the menu and then typing
:set guifont?
This should display to you the string that Vim has set this option to. You'll need to escape any spaces.
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