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add column to mysql table if it does not exist
...e schema, increment the number.
Another solution would be to just try the ALTER TABLE ADD COLUMN command. It should throw an error if the column already exists.
ERROR 1060 (42S21): Duplicate column name 'newcolumnname'
Catch the error and disregard it in your upgrade script.
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Shorten string without cutting words in JavaScript
...g any word off. I know how to use substring, but not indexOf or anything really well.
23 Answers
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How to switch to the new browser window, which opens after click on the button?
..., if that window no more required
driver.close();
// Switch back to original browser (first window)
driver.switchTo().window(winHandleBefore);
// Continue with original browser (first window)
share
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Converting from longitude\latitude to Cartesian coordinates
...rmula", which may be an acceptable amount of error in your case. You will always have some amount of error unless you're talking about a distance of a few feet and even then there is theoretically curvature of the Earth... If you require more rigidly WGS-84 compatible approach checkout the "Vincen...
Vim Regex Capture Groups [bau -> byau : ceu -> cyeu]
...arentheses:
:%s/\(\w\)\(\w\w\)/\1y\2/g
Slightly shorter (and more magic-al) is to use \v, meaning that in the pattern after it all ASCII characters except '0'-'9', 'a'-'z', 'A'-'Z' and '_' have a special meaning:
:%s/\v(\w)(\w\w)/\1y\2/g
See:
:help \(
:help \v
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Ruby on Rails: Where to define global constants?
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If your model is really "responsible" for the constants you should stick them there. You can create class methods to access them without creating a new object instance:
class Card < ActiveRecord::Base
def self.colours
['white', 'blue'...
Changing the selected option of an HTML Select element
...e <option> elements. I want to use jQuery to check each option's value against a Javascript var . If one matches, I want to set the selected attribute of that option. How would I do that?
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What function is to replace a substring from a string in C?
Given a ( char * ) string, I want to find all occurrences of a substring and replace them with an alternate string. I do not see any simple function that achieves this in <string.h> .
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How to properly seed random number generator
...se if you're setting the seed to the time in a fast loop, you'll probably call it with the same seed many times.
In your case, as you're calling your randInt function until you have a different value, you're waiting for the time (as returned by Nano) to change.
As for all pseudo-random libraries, ...
Build tree array from flat array in javascript
...mplex json file that I have to handle with javascript to make it hierarchical, in order to later build a tree.
Every entry of the json has :
id : a unique id,
parentId : the id of the parent node (which is 0 if the node is a root of the tree)
level : the level of depth in the tree
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