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Aggregate / summarize multiple variables per group (e.g. sum, mean)
...reshape2 package for this task:
require(reshape2)
df_melt <- melt(df1, id = c("date", "year", "month"))
dcast(df_melt, year + month ~ variable, sum)
# year month x1 x2
1 2000 1 -80.83405 -224.9540159
2 2000 2 -223.76331 -288.2418017
3 2000 3 -188.83930 -481.560...
How to check if a specified key exists in a given S3 bucket using Java
...
Update:
It seems there's a new API to check just that. See another answer in this page: https://stackoverflow.com/a/36653034/435605
Original post:
Use errorCode.equals("NoSuchKey")
try {
AmazonS3 s3 = new AmazonS3Client(new ClasspathPropertiesFi...
How do I get a distinct, ordered list of names from a DataTable using LINQ?
...plit it up into multiple LINQ statements.
First, select your data into a new list, let's call it x1, do a projection if desired
Next, create a distinct list, from x1 into x2, using whatever distinction you require
Finally, create an ordered list, from x2 into x3, sorting by whatever you desire
...
How can I get the current screen orientation?
...ecated now. Please use getSize(Point outsize). It can be used as passing new point object and that will get its x and y members.
– Mahendra Chhimwal
Sep 24 '15 at 4:49
...
Git update submodules recursively
...unction () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f10168449%2fgit-update-submodules-recursively%23new-answer', 'question_page');
}
);
...
Best way to read a large file into a byte array in C#?
...est = ...
using(Stream source = File.OpenRead(path)) {
byte[] buffer = new byte[2048];
int bytesRead;
while((bytesRead = source.Read(buffer, 0, buffer.Length)) > 0) {
dest.Write(buffer, 0, bytesRead);
}
}
...
How to write Unicode characters to the console?
...unction () {
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}
);
...
What are the benefits to marking a field as `readonly` in C#?
...at once the object is fully constructed, that field cannot be pointed to a new value.
However "readonly" is very different from other types of read-only semantics because it's enforced at runtime by the CLR. The readonly keyword compiles down to .initonly which is verifiable by the CLR.
The rea...
How does grep run so fast?
.... Moreover, GNU grep AVOIDS BREAKING THE INPUT INTO
LINES. Looking for newlines would slow grep down by a factor of
several times, because to find the newlines it would have to look at
every byte!
So instead of using line-oriented input, GNU grep reads raw data into
a large buffer, se...
Manually put files to Android emulator SD card
...m just having trouble with getting my emulator SD card work...
I created a new AVD device with a new SD card.
6 Answers
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