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Increment a value in Postgres
...table 'totals' had 2 columns, 'name' and 'total', and Bill had a total of 203, what would be the SQL statement I'd use in order to move Bill's total to 204?
...
How to prevent browser page caching in Rails
...nse.headers["Pragma"] = "no-cache"
response.headers["Expires"] = "Mon, 01 Jan 1990 00:00:00 GMT"
end
end
Rails 4 and older versions:
class ApplicationController < ActionController::Base
before_filter :set_cache_headers
private
def set_cache_headers
response.headers["Cache-Co...
Python's “in” set operator
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101
Yes, but it also means hash(b) == hash(x), so equality of the items isn't enough to make them t...
How to create enum like type in TypeScript?
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TypeScript 0.9+ has a specification for enums:
enum AnimationType {
BOUNCE,
DROP,
}
The final comma is optional.
share
|
...
How do I check out a specific version of a submodule using 'git submodule'?
...ing the change to the parent repository.
$ cd submodule
$ git checkout v2.0
Previous HEAD position was 5c1277e... bumped version to 2.0.5
HEAD is now at f0a0036... version 2.0
git-status on the parent repository will now report a dirty tree:
# On branch dev [...]
#
# modified: submodule (n...
How exactly does a generator comprehension work?
... # notice it's a generator object
<generator object <genexpr> at 0x7f2ad75f89e0>
>>> len(filtered_gen) # So technically, it has no length
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: object of type 'generator' has no len()
>...
Grouping functions (tapply, by, aggregate) and the *apply family
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10 Answers
10
Active
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PHP regular expressions: No ending delimiter '^' found in
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PHP regex strings need delimiters. Try:
$numpattern="/^([0-9]+)$/";
Also, note that you have a lower case o, not a zero. In addition, if you're just validating, you don't need the capturing group, and can simplify the regex to /^\d+$/.
Example: http://ideone.com/Ec3zh
See also:...
How to redirect output with subprocess in Python?
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20
UPDATE: os.system is discouraged, albeit still available in Python 3.
Use os.system:
os.syst...
Check if value is in select list with JQuery
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180
Use the Attribute Equals Selector
var thevalue = 'foo';
var exists = 0 != $('#select-box option...