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dplyr: “Error in n(): function should not be called directly”
I am attempting to reproduce one of the examples in the dplyr package but am getting this error message. I am expecting to see a new column n produced with the frequency of each combination. What am I missing? I triple checked that the package is loaded.
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PostgreSQL “DESCRIBE TABLE”
How do you perform the equivalent of Oracle's DESCRIBE TABLE in PostgreSQL (using the psql command)?
22 Answers
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cleanest way to skip a foreach if array is empty [duplicate]
Not a major problem but I was wondering if there is a cleaner way to do this. It would be good to avoid nesting my code with an unnecessary if statement. If $items is empty php throws an error.
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Why should a Java class implement comparable?
Why is Java Comparable used? Why would someone implement Comparable in a class? What is a real life example where you need to implement comparable?
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What is a semaphore?
... a programming concept that is frequently used to solve multi-threading problems. My question to the community:
14 Answer...
How to thoroughly purge and reinstall postgresql on ubuntu? [closed]
Somehow I've managed to completely bugger the install of postgresql on Ubuntu karmic. I want to start over from scratch, but when I "purge" the package with apt-get it still leaves traces behind such that the reinstall configuration doesn't run properly.
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Find and Replace text in the entire table using a MySQL query
Usually I use manual find to replace text in a MySQL database using phpmyadmin. I'm tired of it now, how can I run a query to find and replace a text with new text in the entire table in phpmyadmin?
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Bower: ENOGIT Git is not installed or not in the PATH
Git is installed and is in the path.
16 Answers
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What is the difference between atomic and critical in OpenMP?
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The effect on g_qCount is the same, but what's done is different.
An OpenMP critical section is completely general - it can surround any arbitrary block of code. You pay for that generality, however, by incurring significant overhead ev...
Where to place the 'assets' folder in Android Studio?
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Since Android Studio uses the new Gradle-based build system, you should be putting assets/ inside of the source sets (e.g., src/main/assets/).
In a typical Android Studio project, you will have an app/ module, with a main/ sourceset (app/src/main/ off of the ...