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LINQ: When to use SingleOrDefault vs. FirstOrDefault() with filtering criteria
...an return any amount of results but you state that you only want the first one.
I personally find the semantics very different and using the appropriate one, depending on the expected results, improves readability.
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Simple regular expression for a decimal with a precision of 2
...?)?
More compact:
\d+(\.\d{1,2})?
Both assume that both have at least one digit before and one after the decimal place.
To require that the whole string is a number of this form, wrap the expression in start and end tags such as (in Perl's form):
^\d+(\.\d{1,2})?$
To match numbers without a...
Check if OneToOneField is None in Django
...
To check if the (OneToOne) relation exists or not, you can use the hasattr function:
if hasattr(request.user, 'type1profile'):
# do something
elif hasattr(request.user, 'type2profile'):
# do something else
else:
# do something el...
How to assign from a function which returns more than one value?
...;- functionReturningTwoValues()
If you only need the first or second component these all work too:
list[a] <- functionReturningTwoValues()
list[a, ] <- functionReturningTwoValues()
list[, b] <- functionReturningTwoValues()
(Of course, if you only needed one value then functionReturning...
I want to copy table contained from one database and insert onto another database table
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If you want to copy a table from one Database to another database , You can simply do as below.
CREATE TABLE db2.table LIKE db1.table;
INSERT INTO db2.table SELECT * FROM db1.table;
...
Define all functions in one .R file, call them from another .R file. How, if possible?
...ions are changing a lot since you are converting the code, put them all in one file and just source the whole thing every time. You could also have a separate smaller file that 1. sources the larger collection of functions and 2. Runs your test cases. In R there are lots of ways to arrange your wo...
Do on-demand Mac OS X cloud services exist, comparable to Amazon's EC2 on-demand instances? [closed]
...ather they don't backup your files, hence use of DropBox to do the backup. One should contact them to clarify this if desired.
They have various pricing options, as you mention the all day pass, monthly plans at $20, and their is a pay as you go plan at $1/hr. I'd probably go with pay as you go bas...
Difference between .on('click') vs .click()
... a single handler for all elements that match your selector, including the ones created dynamically.
...another reason to use .on
As Adrien commented below, another reason to use .on is namespaced events.
If you add a handler with .on("click", handler) you normally remove it with .off("click",...
Extract a dplyr tbl column as a vector
Is there a more succinct way to get one column of a dplyr tbl as a vector, from a tbl with database back-end (i.e. the data frame/table can't be subset directly)?
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private final static attribute vs private final attribute
...t same data. Compare this with an instance variable: in that case, there's one independent version of the variable per instance of the class. So for example:
Test x = new Test();
Test y = new Test();
x.instanceVariable = 10;
y.instanceVariable = 20;
System.out.println(x.instanceVariable);
prints ...