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JSON Stringify changes time of date because of UTC
... currentDate = new Date();
currentDate = JSON.stringify(currentDate);
// Now currentDate is in a different format... oh gosh what do we do...
currentDate = new Date(JSON.parse(currentDate));
// Now currentDate is back to its original form :)
...
Elegant way to invert a map in Scala
... different keys associated with same values. So, if you are interested in knowing all the keys, here's the code:
scala> val m = Map(1 -> "a", 2 -> "b", 4 -> "b")
scala> m.groupBy(_._2).mapValues(_.keys)
res0: Map[String,Iterable[Int]] = Map(b -> Set(2, 4), a -> Set(1))
...
Comparing two java.util.Dates to see if they are in the same day
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This uses an external dependency... but it's good to know for the future.
– Jason S
Mar 25 '10 at 18:06
20
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Get form data in ReactJS
...se React's two-way databinding helper mixin to achieve the same thing, but now it's deprecated in favor of setting the value and change handler (as above):
var ExampleForm = React.createClass({
mixins: [React.addons.LinkedStateMixin],
getInitialState: function() {
return {email: '', passwor...
EC2 instance has no public DNS
...
The section containing VPCs is now called Networking. And to edit, you right-click on the VPC.
– nasch
May 20 '15 at 19:31
92
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How to set auto increment primary key in PostgreSQL?
...plog_adfarm_seq'),
'Will the smart cookies catch the crumb? Find out now!'
);
Step 4, observe the rows
el@defiant ~ $ psql -U pgadmin -d kurz_prod -c "select * from splog_adfarm"
splog_key | splog_value
----------+--------------------...
What is the significance of #pragma marks? Why do we need #pragma marks?
...wer showing what pragma marks look like (in that menu or wherever they are now) in the new XCode?
– user7804781
Jul 27 '18 at 17:54
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How do you delete a column by name in data.table?
...hough data.table is gradually moving away from using this argument so it's now discouraged where you can avoid it; showing here so you know the option exists in case you really do need it:
# Method 5a (like Method 3)
df3[, !"foo", with=FALSE]
# Method 5b (like Method 4)
df3[, !grep("^foo$", names(...
Debugging sqlite database on the device
...his will copy your db-file to the root of your SD card / external storage. Now you can easily get it from there by using file manager, adb pull or whatever else you like. Note that with this approach, there is NO need for your app to have WRITE_EXTERNAL_STORAGE permission, as the copying is done by ...
Should try…catch go inside or outside a loop?
...on was getting on my nerves! In the case of optimizations, since we can't know which way the performance would be affected, I guess were back to try-it-and-test (as always).
– Jeffrey L Whitledge
Sep 27 '08 at 18:35
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