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Split comma-separated strings in a column into separate rows
...solution,
and two additional variants of Jaap's data.table methods.
Overall 8 different methods were benchmarked on 6 different sizes of data frames using the microbenchmark package (see code below).
The sample data given by the OP consists only of 20 rows. To create larger data frames, these 20...
Print a file's last modified date in Bash
... to find how to print out the date of a file. I'm so far able to print out all the files in a directory, but I need to print out the dates with it.
...
Android: create a popup that has multiple selection options
... Toast.makeText(TopicDetails.this, "you nailed it", Toast.LENGTH_SHORT).show();
} else if ("Medium".equals(fonts[which])) {
Toast.makeText(TopicDetails.this, "you cracked it", Toast.LENGTH_SHORT).show();
} else if ("Large".equals(fonts[which])) {
...
Reading a plain text file in Java
...
I'd also recommend you download and read this wonderful (yet free) book called Thinking In Java
In Java 7:
new String(Files.readAllBytes(...))
(docs)
or
Files.readAllLines(...)
(docs)
In Java 8:
Files.lines(..).forEach(...)
(docs)
...
Converting RGB to grayscale/intensity
...ly different numbers / different methods,
you won't see much difference at all on a normal computer screen
under normal lighting conditions -- try it.
Here are some more links on color in general:
Wikipedia Luma
Bruce Lindbloom 's outstanding web site
chapter 4 on Color in the book by Colin Wa...
NoSQL - MongoDB vs CouchDB [closed]
...~2.5Gb
Text search integrated
GridFS to store big data + metadata (not actually an FS)
Data center aware
Best used: If you need dynamic queries. If you prefer to define indexes, not map/reduce functions. If you need good performance on a big DB. If you wanted CouchDB, but your data changes too muc...
Select multiple images from android gallery
So basically what i am trying to achieve is opening the Gallery in Android and let the user select multiple images . Now this question has been asked frequently but i'm not satisfied with the answers. Mainly because i found something interesting in de docs in my IDE (i come back on this later) ...
What are all the common undefined behaviours that a C++ programmer should know about? [closed]
What are all the common undefined behaviours that a C++ programmer should know about?
11 Answers
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Handling JSON Post Request in Go
...can't find an example of Go handling a POST request of JSON data. They are all form POSTs.
7 Answers
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how to show lines in common (reverse diff)?
...ile2, and they have both overlapping and non-overlapping rows. If you want all and only the non-overlapping rows, using fgrep -v file1 file2 will only return the non-overlapping rows in file2, and none of the additional non-overlapping rows in file1. This may be obvious to some, but better to state ...