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How to execute mongo commands through shell scripts?
...ate({\"name\":\"foo\"},{$set:{\"this\":\"that\"}});"
> E QUERY SyntaxError: Unexpected token :
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How can I convert a string to a number in Perl?
...wever, if $var is string could not be converted to numeric, you'll get the error, and $var will be reset to 0:
my $var = 'abc123';
print "var = $var\n";
$var += 0;
print "var = $var\n";
logs
var = abc123
Argument "abc123" isn't numeric in addition (+) at test.pl line 7.
var = 0
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What does !! mean in ruby?
...pying from Matt Van Horn's answer with slight modifications:
1 ^ true
TypeError: can't convert true into Integer
!!1 ^ !!true
=> false
I used it to ensure two variables were either both nil, or both not nil.
raise "Inconsistency" if !!a ^ !!b
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Creating a “logical exclusive or” operator in Java
...ated.
This is especially useful if the second operand would results in an error.
e.g.
if (set == null || set.isEmpty())
// or
if (list != null && list.size() > 0)
However with XOR, you always have to evaluate the second operand to get the result so the only meaningful operation is ^.
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How can I do an UPDATE statement with JOIN in SQL Server?
...FAIK, this kind of operation would expect a scalar value and will throw an error if given a result set instead.
– Francis Lord
May 16 '17 at 16:31
7
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What's the difference between & and && in MATLAB?
...ntees a condition without which the second expression may cause a run-time error. e.g. d != 0 && 1/d vs d !=0 & 1/d - the first guarantees no division by zero, the second doesn't.
– Fraser
Nov 14 '16 at 17:06
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What reference do I need to use Microsoft.Office.Interop.Excel in .NET?
...ws 7 PC, but even after installing the PIA's on the server, I still get an error message about System.Runtime.Interop.COM components missing. The program breaks when I try to instantiate the Excel.Application() object. Is there anything else I'm missing?
– Melanie
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Cannot install Lxml on Mac os x 10.9
...e:
brew unlink libxml2
brew unlink libxslt
If you are having permission errors with Homebrew, especially on El Capitan, this is a helpful document. In essence, regardless of OS X version, try running:
sudo chown -R $(whoami):admin /usr/local
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How do I loop through a list by twos? [duplicate]
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what about about float value? I got error that integer argument expected, got float
– Kevin Patel
Mar 5 at 10:48
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Convert an NSURL to an NSString
... I used NSString *urlString = [myURL absoluteString]; But I had met this error and xcode was crashed. -[__NSCFString absoluteString]: unrecognized selector sent to instance 0x791a18e0
– Võ Mai Trinh
Jun 22 '15 at 9:39
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