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In Jinja2, how do you test if a variable is undefined?
... Additionally, you can use {% if variable is not defined %} to test the inverse.
– pbaranay
Feb 22 '17 at 15:37
...
How to rethrow InnerException without losing stack trace in C#?
...ctManager calls SetObjectData
// voila, e is unmodified save for _remoteStackTraceString
}
This wastes a lot of cycles compared to calling InternalPreserveStackTrace via cached delegate, but has the advantage of relying only on public functionality. Here are a couple of common usage patterns ...
How do you set a default value for a MySQL Datetime column?
...ith DATETIME...
But you can do it with TIMESTAMP:
mysql> create table test (str varchar(32), ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP);
Query OK, 0 rows affected (0.00 sec)
mysql> desc test;
+-------+-------------+------+-----+-------------------+-------+
| Field | Type | Null | Key | ...
How do you check if a variable is an array in JavaScript? [duplicate]
... the one you have chosen.
variable.constructor === Array
This is the fastest method on Chrome, and most likely all other browsers. All arrays are objects, so checking the constructor property is a fast process for JavaScript engines.
If you are having issues with finding out if an objects proper...
Specifying colClasses in the read.csv
...nly one columns.
So in your example you should use:
data <- read.csv('test.csv', colClasses=c("time"="character"))
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In Python, if I return inside a “with” block, will the file still close?
... experiment to show the guarantee you get from the finally keywrod is: def test(): try: return True; finally: return False.
– Ehsan Kia
Jul 11 '14 at 19:57
...
Disable ActiveRecord for Rails 4
...require "action_mailer/railtie"
require "sprockets/railtie"
require "rails/test_unit/railtie"
Remove config.active_record.raise_in_transactional_callbacks = true from config/application.rb
3. Delete your config/database.yml file, db/schema.rb and migrations (if any)
4. Delete migration check in ...
Java 8 NullPointerException in Collectors.toMap
...ault non-overloaded version instead. Maybe merge is faster, but I have not tested.
– Brett Ryan
Oct 19 '15 at 12:59
1
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How to reference generic classes and methods in xml documentation
...t completely resolves.
If the method in the OP were in a namespace called Test, the completely resolved link to the method shown would be:
<see cref="M:Test.FancyClass`1.FancyMethod``1(`0)"/>
As you may be able to work out, there should only be one backtick before the number of class type p...
Efficiency of premature return in a function
...
There is no difference at all:
=====> cat test_return.cpp
extern void something();
extern void something2();
void test(bool b)
{
if(b)
{
something();
}
else
something2();
}
=====> cat test_return2.cpp
extern void something();
exter...