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Can dplyr package be used for conditional mutating?
... TRUE ~ NA_real_))
Added - arithmetic/na_if If the values are numeric and the conditions (except for the default value of NA at the end) are mutually exclusive, as is the case in the question, then we can use an arithmetic expression such that each term is multiplied by the desired result using...
How to encode a URL in Swift [duplicate]
...3.0
var address = "American Tourister, Abids Road, Bogulkunta, Hyderabad, Andhra Pradesh, India"
let escapedAddress = address.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
let urlpath = String(format: "http://maps.googleapis.com/maps/api/geocode/json?address=\(escapedAd...
Error handling in C code
What do you consider "best practice" when it comes to error handling errors in a consistent way in a C library.
22 Answers
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MongoDB/NoSQL: Keeping Document Change History
...his approach is fine though when you're dealing with small-sized documents and/or don't update documents very often.
Only store changes in a new version
Another approach would be to store only the changed fields in a new version. Then you can 'flatten' your history to reconstruct any version of th...
What should a Multipart HTTP request with multiple files look like? [duplicate]
... to mind immediately: 1) write your loop as (print boundary, print stuff), and then after the for loop completes follow that with (print boundary with extra dashes). That's probably the easiest way. 2) write your for() loop to run whatever index variable you have down to 0, instead of up from 0. The...
How to determine if binary tree is balanced?
... move to do some actual programming now. I'm working on binary trees now, and I was wondering what would be the best way to determine if the tree is height-balanced.
...
What does a colon following a C++ constructor name do? [duplicate]
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This is an initialization list, and is part of the constructor's implementation.
The constructor's signature is:
MyClass();
This means that the constructor can be called with no parameters. This makes it a default constructor, i.e., one which will be ca...
iOS start Background Thread
... is responsible for setting up the new thread's autorelease pool, run loop and other configuration details – see "Using NSObject to Spawn a Thread" in Apple's Threading Programming Guide.
You'd probably be better off using Grand Central Dispatch, though:
dispatch_async(dispatch_get_global_queue(...
Find UNC path of a network drive?
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In Windows, if you have mapped network drives and you don't know the UNC path for them, you can start a command prompt (Start → Run → cmd.exe) and use the net use command to list your mapped drives and their UNC paths:
C:\>net use
New connections will be remember...
Why do loggers recommend using a logger per class?
...u still do this, but you can do it once per class instead of once per call and eliminate a serious performance problem.
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