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What are the differences between “=” and “
...aced list of expressions (i.e. {…; …}). — Without further ado:
x
# Error: object 'x' not found
sum((x = 1), 2)
# [1] 3
x
# [1] 1
Clearly we’ve performed an assignment, using =, outside of contexts (a) and (b). So, why has the documentation of a core R language feature been wrong for deca...
find() with nil when there are no records
...in
user = User.find(10)
rescue ActiveRecord::RecordNotFound
puts "some error msg"
end
If you want to recover from the error in the rescue block (e.g. by setting a placeholder user (null pattern)), you can continue with your code below this block. Otherwise you might just put all your code for ...
What is the effect of extern “C” in C++?
...
@Anne, no, I think you've been affected by some other error in the source, because what you are describing is wrong. No version of g++ got this wrong, for any target, at any time in the last 17 years at least. The whole point of the first example is that it doesn't matter whethe...
Adding a new value to an existing ENUM Type
...ou are using db-migrate (which runs in transaction), then you might get an error: ERROR: ALTER TYPE ... ADD cannot run inside a transaction block The solution is mentioned here (by Hubbitus): stackoverflow.com/a/41696273/1161370
– Mahesh
Oct 26 '17 at 19:24
...
Test whether string is a valid integer
...q "$1" ] 2>/dev/null
then
echo "$1 is an integer !!"
else
echo "ERROR: first parameter must be an integer."
echo $USAGE
exit 1
fi
This approach also accounts for negative numbers, which some of the other solutions will have a faulty negative result, and it will allow a prefix of...
How do I daemonize an arbitrary script in unix?
...our session. The only minor problem with this is standard out and standard error both get sent to ./nohup.out, so if you start several scripts in this manor their output will be intertwined. A better command would be:
nohup yourScript.sh script args >script.out 2>script.error&
This will...
Gem::LoadError for mysql2 gem, but it's already in Gemfile
This error occurred while loading the following files:
14 Answers
14
...
How does the “final” keyword in Java work? (I can still modify an object.)
... of the class. Again, if the variable is static then it is a compilation error.
18 Answers
...
Safely turning a JSON string into an object
...SON.parse, the program MAY continue "successfully" but you'll still see an error thrown in the console with the dreaded "Error: unexpected token 'x'".
var data;
try {
data = JSON.parse(jqxhr.responseText);
} catch (_error) {}
data || (data = {
message: 'Server error, please retry'
});
...
form serialize javascript (no framework)
...ee, googlecode does not work without javascript. It simply spits That's an error
– user1040495
Apr 17 '17 at 14:35
3
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