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How to select a single field for all documents in a MongoDB collection?
... MongoDB, I have a student collection with 10 records having fields name and roll . One record of this collection is:
1...
HTML5 Email Validation
...your email">
<input type="submit" value="Submit">
</form>
And when the user press submit, it automatically shows an error message like:
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How to linebreak an svg text within javascript?
...cur, you can break your text into multiple <tspan>s, each with x="0" and dy="1.4em" to simulate actual lines of text. For example:
<g transform="translate(123 456)"><!-- replace with your target upper left corner coordinates -->
<text x="0" y="0">
<tspan x="0" dy="1...
Display open transactions in MySQL
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How can I display these open transactions and commit or cancel them?
There is no open transaction, MySQL will rollback the transaction upon disconnect.
You cannot commit the transaction (IFAIK).
You display threads using
SHOW FULL PROCESSLIST
See: http:/...
How do I retrieve the number of columns in a Pandas data frame?
How do you programmatically retrieve the number of columns in a pandas dataframe? I was hoping for something like:
6 Answer...
How do I adjust the anchor point of a CALayer, when Auto Layout is being used?
...at in layoutSubviews the runtime comes dashing through all the constraints and setting the frames of all the views accordingly.
In other words, the constraints are not magic; they are just a to-do list. layoutSubviews is where the to-do list gets done. And it does it by setting frames.
I can't hel...
My attempt at value initialization is interpreted as a function declaration, and why doesn't A a(())
...ression, while () is not.
To learn more about how languages are defined, and how compilers work, you should learn about Formal language theory or more specifically Context Free Grammars (CFG) and related material like finite state machines. If you are interested in that though the wikipedia pages...
Getting output of system() calls in Ruby
If I call a command using Kernel#system in Ruby, how do I get its output?
15 Answers
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printf() formatting for hex
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The # part gives you a 0x in the output string. The 0 and the x count against your "8" characters listed in the 08 part. You need to ask for 10 characters if you want it to be the same.
int i = 7;
printf("%#010x\n", i); // gives 0x00000007
printf("0x%08x\n", i); // gives 0x0...
Why doesn't indexOf work on an array IE8?
The below function works fine on Opera, Firefox and Chrome. However, in IE8 it fails on the if ( allowed.indexOf(ext[1]) == -1) part.
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