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Compare two data.frames to find the rows in data.frame 1 that are not present in data.frame 2
...<- data.frame(a = 1:3, b = letters[1:3])
comparison <- compare(a1,a2,allowAll=TRUE)
comparison$tM
# a b
#1 1 a
#2 2 b
#3 3 c
The function compare gives you a lot of flexibility in terms of what kind of comparisons are allowed (e.g. changing order of elements of each vector, changing order a...
EF Code First “Invalid column name 'Discriminator'” but no inheritance
I have a table in my database called SEntries (see below the CREATE TABLE statement). It has a primary key, a couple of foreign keys and nothing special about it. I have many tables in my database similar to that one, but for some reason, this table ended up with a "Discriminator" column on the EF P...
Purpose of memory alignment
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It's a limitation of many underlying processors. It can usually be worked around by doing 4 inefficient single byte fetches rather than one efficient word fetch, but many language specifiers decided it would be easier just to outlaw them and force everything to be aligned.
There is ...
Why is the tag deprecated in HTML?
...n property to center. This guarantees that the element will be centered in all modern browsers.
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Algorithm to find Largest prime factor of a number
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Actually there are several more efficient ways to find factors of big numbers (for smaller ones trial division works reasonably well).
One method which is very fast if the input number has two factors very close to its square r...
How do I iterate through the files in a directory in Java?
I need to get a list of all the files in a directory, including files in all the sub-directories. What is the standard way to accomplish directory iteration with Java?
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Viewing my IIS hosted site on other machines on my network
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As others said your Firewall needs to be configured to accept incoming calls on TCP Port 80.
in win 7+ (easy wizardry way)
go to windows firewall with advance security
Inbound Rules -> Action -> New Rule
select Predefined radio button and t...
Error type 3 Error: Activity class {} does not exist
...the Build directory
Restarted Android Studio
Rebuild the Project
Run
Optionally (Go to the files menu on android, click on "Invalidate Caches / Restart..." uninstall the app on your phone and try again)
And everything worked fine!
I think the key is to restart your IDE.
Hope this helps you or a...
How do I find out what version of WordPress is running?
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Excellent tip that allows for quickly checking without looking up credentials for any one of 100 client accounts and log in to the FTP! An even quicker way is to "Click the W logo" as per the below answer - again, if you have credentials at the...
Java LinkedHashMap get first or last entry
... entry is possible, but will entail iterating over the whole entry set by calling .next() until you reach the last. while (iterator.hasNext()) { lastElement = iterator.next() }
edit: However, if you're willing to go beyond the JavaSE API, Apache Commons Collections has its own LinkedMap implementa...