大约有 45,000 项符合查询结果（耗时：0.0593秒） [XML]
How do you do relative time in Rails?
... i.e. if given a certain Time class, it can calculate "30 seconds ago" or "2 days ago" or if it's longer than a month "9/1/2008", etc.
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Cluster analysis in R: determine the optimal number of clusters
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1024
If your question is how can I determine how many clusters are appropriate for a kmeans analysis...
How to validate IP address in Python? [duplicate]
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answered Nov 25 '08 at 23:50
DustinDustin
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Measuring the distance between two coordinates in PHP
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12 Answers
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What are bitwise shift (bit-shift) operators and how do they work?
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1728
The bit shifting operators do exactly what their name implies. They shift bits. Here's a brie...
How to convert a string or integer to binary in Ruby?
... number to a string representing the number in the base specified:
9.to_s(2) #=> "1001"
while the reverse is obtained with String#to_i(base):
"1001".to_i(2) #=> 9
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How does python numpy.where() work?
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answered Apr 12 '11 at 22:48
Joe KingtonJoe Kington
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How to Batch Rename Files in a macOS Terminal?
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234
In your specific case you can use the following bash command (bash is the default shell on mac...
Resizing an image in an HTML5 canvas
...g.height;
elem.style.display = "none";
this.ctx = elem.getContext("2d");
this.ctx.drawImage(img, 0, 0);
this.img = img;
this.src = this.ctx.getImageData(0, 0, img.width, img.height);
this.dest = {
width : sx,
height : Math.round(img.height * sx / img.width),
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Omit rows containing specific column of NA
... function and put it into a function thusly:
DF <- data.frame(x = c(1, 2, 3), y = c(0, 10, NA), z=c(NA, 33, 22))
completeFun <- function(data, desiredCols) {
completeVec <- complete.cases(data[, desiredCols])
return(data[completeVec, ])
}
completeFun(DF, "y")
# x y z
# 1 1 0 NA
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