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Python None comparison: should I use “is” or ==?
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is checks for object identity. There is only 1 object None, so when you do my_var is None, you're checking whether they actually are the same object (not just equivalent objects)
In other words, == is a check for equivalence (which is defined from object to object) whereas is checks for object ...
How do I import CSV file into a MySQL table?
...ce import dialogs for this kind of thing.
My favourite for the job is Windows based HeidiSQL. It gives you a graphical interface to build the LOAD DATA command; you can re-use it programmatically later.
Screenshot: "Import textfile" dialog
To open the Import textfile" dialog, go to Tools > ...
Jquery select all elements that have $jquery.data()
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You could do
$('[data-myAttr!=""]');
this selects all elements which have an attribute data-myAttr which is not equal to '' (so it must have been set);
you could also use filter()
$('*').filter(function() {
return $(this).dat...
How do I associate file types with an iPhone application?
...ustom URL schemes. You can register your application to handle particular document types, and any application that uses a document controller can hand off processing of these documents to your own application.
For example, my application Molecules (for which the source code is available) handles t...
Why is __init__() always called after __new__()?
...r returning a new
instance of your class.
In contrast,
__init__ doesn't return anything; it's only responsible for initializing the
instance after it's been created.
In general, you shouldn't need to
override __new__ unless you're
subclassing an immutable type like
str, int, ...
Linux command (like cat) to read a specified quantity of characters
...d discard the rest.
To just get the first five bytes from standard input, do:
dd count=5 bs=1
Note that, if you want to specify the input file name, dd has old-fashioned argument parsing, so you would do:
dd count=5 bs=1 if=filename
Note also that dd verbosely announces what it did, so to tos...
How can I unstage my files again after making a local commit?
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git reset --soft HEAD~1 should do what you want. After this, you'll have the first changes in the index (visible with git diff --cached), and your newest changes not staged. git status will then look like this:
# On branch master
# Changes to be committed...
Count number of records returned by group by
How do I count the number of records returned by a group by query,
13 Answers
13
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Dynamic variable names in Bash
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Hmm. I'm using bash 4.2.45(2) and declare doesn't list it as an option declare: usage: declare [-afFirtx] [-p] [name[=value] ...]. It seems to be working correctly however.
– fent
Dec 2 '13 at 15:56
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How to elegantly check if a number is within a range?
How can I do this elegantly with C# and .NET 3.5/4?
27 Answers
27
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