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Remove columns from dataframe where ALL values are NA
...ect the same size as df.
Here are two approaches that are more memory and time efficient
An approach using Filter
Filter(function(x)!all(is.na(x)), df)
and an approach using data.table (for general time and memory efficiency)
library(data.table)
DT <- as.data.table(df)
DT[,which(unlist(lapp...
Reuse a parameter in String.format?
Does the hello variable need to be repeated multiple times in the call to the format method or is there a shorthand version that lets you specify the argument once to be applied to all of the %s tokens?
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Parsing huge logfiles in Node.js - read in line-by-line
... readline module is a pain. It does not pause and was causing failure everytime after 40-50 million. Wasted a day. Thanks a lot for the answer. This one works perfectly
– Mandeep Singh
Jun 7 '16 at 17:42
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How to Validate a DateTime in C#?
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DateTime.TryParse
This I believe is faster and it means you dont have to use ugly try/catches :)
e.g
DateTime temp;
if(DateTime.TryParse(startDateTextBox.Text, out temp))
{
// Yay :)
}
else
{
// Aww.. :(
}
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Detect encoding and make everything UTF-8
...ing is returned unchanged. One call to fixUTF8() takes at least twice the time of a call to forceUTF8(), so it's a lot less performant. I made fixUTF8() just to create a command line program that would fix "encode-corrupted" files, but in a live environment is rarely needed.
–...
I have 2 dates in PHP, how can I run a foreach loop to go through all of those days?
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Requires PHP5.3:
$begin = new DateTime('2010-05-01');
$end = new DateTime('2010-05-10');
$interval = DateInterval::createFromDateString('1 day');
$period = new DatePeriod($begin, $interval, $end);
foreach ($period as $dt) {
echo $dt->format("l Y-m-d ...
Random alpha-numeric string in JavaScript? [duplicate]
... seems to have some problems. As you can see from THIS screenshot, it sometimes generates strings that aren't the specified length. I put your randomString(..) function in a for(var i=0;i<50;i++){} loop that generated 50 random strings, and the last one is three characters long. I also told it...
How can I use map and receive an index as well in Scala?
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Or, assuming your collection has constant access time, you could map the list of indexes instead of the actual collection:
val ls = List("a","b","c")
0.until(ls.length).map( i => doStuffWithElem(i,ls(i)) )
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How can I split a JavaScript string by white space or comma?
...y should have tested it before I made that last edit. I have now, and this time it really should work.
– KaptajnKold
Mar 22 '13 at 12:50
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Using multiple delimiters in awk
...r # or a space, where the separating character must be repeated at least 2 times and not more than 6 times, for example:
awk -F'[2-5a# ]{2,6}' ...
I am sure variations of this exist using ( ) and parameters
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