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Count number of rows within each group
I have a dataframe and I would like to count the number of rows within each group. I reguarly use the aggregate function to sum data as follows:
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What is string_view?
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The purpose of any and all kinds of "string reference" and "array reference" proposals is to avoid copying data which is already owned somewhere else and of which only a non-mutating view is required. The string_view in question is one such pro...
Python: Why is functools.partial necessary?
...h lambdas?
Not much in terms of extra functionality (but, see later) – and, readability is in the eye of the beholder.
Most people who are familiar with functional programming languages (those in the Lisp/Scheme families in particular) appear to like lambda just fine – I say "most", definitely...
ADB No Devices Found
I am attempting to install an Android app on my brand new Nexus 10 . I have a .apk file. I have downloaded the Android SDK, installed "Android SDK Tools", "Android SDK Platform-tools", and Google USB Driver. I have checked the setting on my Nexus 10 for "Unknown Sources".
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How to automatically generate N “distinct” colors?
...similar. I can also imagine evenly subdividing the RGB cube into a lattice and then drawing points. Does anyone know any other methods? I'm ruling out defining a list and then just cycling through it. I should also say I don't generally care if they clash or don't look nice, they just have to be vis...
Remove all subviews?
...h thanks to cocoafan: This situation is muddled up by the fact that NSView and UIView handle things differently. For NSView (desktop Mac development only), you can simply use the following:
[someNSView setSubviews:[NSArray array]];
For UIView (iOS development only), you can safely use makeObjects...
Getting All Variables In Scope
...nk to the official page where you can download the canonical spec (a PDF), and here's one to the official, linkable HTML version.
Update based on your comment to Camsoft
The variables in scope for your event function are determined by where you define your event function, not how they call it. But...
Protecting executable from reverse engineering?
I've been contemplating how to protect my C/C++ code from disassembly and reverse engineering. Normally I would never condone this behavior myself in my code; however the current protocol I've been working on must not ever be inspected or understandable, for the security of various people.
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Filtering by Multiple Specific Model Properties in AngularJS (in OR relationship)
... is the plunker
New plunker with cleaner code & where both the query and search list items are case insensitive
Main idea is create a filter function to achieve this purpose.
From official doc
function: A predicate function can be used to write arbitrary filters.
The function is called...
iPhone App Minus App Store?
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Official Developer Program
For a standard iPhone you'll need to pay the US$99/yr to be a member of the developer program. You can then use the adhoc system to install your application onto up to 100 devices. The developer program has the details but it involve...