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What does the construct x = x || y mean?
...o if you call the method with no arguments it will use a default value of "Error".
It's shorthand for writing:
if (!title) {
title = "Error";
}
This kind of shorthand trick with boolean expressions is common in Perl too. With the expression:
a OR b
it evaluates to true if either a or b is t...
Stop and Start a service via batch or cmd file?
How can I script a bat or cmd to stop and start a service reliably with error checking (or let me know that it wasn't successful for whatever reason)?
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rsync error: failed to set times on “/foo/bar”: Operation not permitted
I'm getting a confusing error from rsync and the initial things I'm finding from web searches (as well as all the usual chmod'ing) are not solving it:
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Command not found error in Bash variable assignment
... If you have a variable with a name that contaings "-", the same error happens. In that case, the solution is to remove the "-"
– chomp
Jun 17 '16 at 2:27
1
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Python: try statement in a single line
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Some people abuse the short-circuiting behavior of or to do this. This is error prone, so I never use it.
c = None
b = [1, 2]
a = c or b
Consider the following case:
c = []
b = [1, 2]
a = c or b
In this case, a probably should be [], but it is [1, 2] because [] is false in a boolean context. ...
Swift compiler error: “non-modular header inside framework module”
...I would like to migrate my ObjC framework to Swift and I got the following error:
20 Answers
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Strange SQLAlchemy error message: TypeError: 'dict' object does not support indexing
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I wish they would of updated that error message, every time I get it I end up landing on this page and answer
– oshi2016
Mar 16 '17 at 5:46
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How to unload a package without restarting R
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> detach("package:MASS", unload=TRUE) Error in detach("package:MASS", unload = TRUE) : invalid 'name' argument
– Mona Jalal
Feb 12 '14 at 2:39
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mongodb, replicates and error: { “$err” : “not master and slaveOk=false”, “code” : 13435 }
...eversely (primary to secondary and vice versa) and we are getting the same error.
so please check in the configuration settings for database status which may help you.
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PostgreSQL error 'Could not connect to server: No such file or directory'
Like some others I am getting this error when I run rake db:migrate in my project or even try most database tasks for my Ruby on Rails 3.2 applications.
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