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MySQL, Check if a column exists in a table with SQL
...pecific column, and if not — create it. Otherwise do nothing. This is really an easy procedure in any enterprise-class database, yet MySQL seems to be an exception.
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Find an item in List by LINQ?
Here I have a simple example to find an item in a list of strings. Normally I use for loop or anonymous delegate to do it like this:
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How do I concatenate strings and variables in PowerShell?
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This isn't technically concatenation.
– TravisEz13
Jun 14 '16 at 17:59
9
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Adding git branch on the Bash command prompt
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git 1.9.3 or later: use __git_ps1
Git provides a shell script called git-prompt.sh, which includes a function __git_ps1 that
prints text to add to bash PS1 prompt (includes branch name)
Its most basic usage is:
$ __git_ps1
(master)
It also takes an optional format string:
$ __g...
Understanding the difference between Object.create() and new SomeFunction()
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The object used in Object.create actually forms the prototype of the new object, where as in the new Function() form the declared properties/functions do not form the prototype.
Yes, Object.create builds an object that inherits directly from the one passed as ...
What is your single most favorite command-line trick using Bash? [closed]
We all know how to use <ctrl>-R to reverse search through history, but did you know you can use <ctrl>-S to forward search if you set stty stop "" ? Also, have you ever tried running bind -p to see all of your keyboard shortcuts listed? There are over 455 on Mac OS X by default. ...
How to crop an image in OpenCV using Python
...copy region of interest
If we consider (0,0) as top left corner of image called im with left-to-right as x direction and top-to-bottom as y direction. and we have (x1,y1) as the top-left vertex and (x2,y2) as the bottom-right vertex of a rectangle region within that image, then:
roi = im[y1:y2, x1...
Command-line Unix ASCII-based charting / plotting tool
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While gnuplot is powerful, it's also really irritating when you just want to pipe in a bunch of points and get a graph.
Thankfully, someone created eplot (easy plot), which handles all the nonsense for you.
It doesn't seem to have an option to force terminal gra...
In Django, how do I check if a user is in a certain group?
...add(group) # user is now in the "Editor" group
then user.groups.all() returns [<Group: Editor>].
Alternatively, and more directly, you can check if a a user is in a group by:
if django_user.groups.filter(name = groupname).exists():
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Note that groupname can also be the ac...
How to generate .NET 4.0 classes from xsd?
...or the case you have several interlinked schema definitions just name them all. xsd schema1.xsd schema2.xsd schema3.xsd /c
– mivra
Oct 24 '16 at 19:40
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