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Adding a column to a data.frame
... below. I want to add a column that classifies my data according to column 1 ( h_no ) in that way that the first series of h_no 1,2,3,4 is class 1, the second series of h_no (1 to 7) is class 2 etc. such as indicated in the last column.
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Why does changing 0.1f to 0 slow down performance by 10x?
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Welcome to the world of denormalized floating-point! They can wreak havoc on performance!!!
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What is a regular expression which will match a valid domain name without a subdomain?
...ee comments), given your specific requirements:
/^[a-zA-Z0-9][a-zA-Z0-9-]{1,61}[a-zA-Z0-9]\.[a-zA-Z]{2,}$/
But note this will reject a lot of valid domains.
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Difference between break and continue statement
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Phonegap Cordova installation Windows
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Type-juggling and (strict) greater/lesser-than comparisons in PHP
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edited May 23 '17 at 11:47
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answered Apr 4 '13 at 14:10
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Find indices of elements equal to zero in a NumPy array
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numpy.where() is my favorite.
>>> x = numpy.array([1,0,2,0,3,0,4,5,6,7,8])
>>> numpy.where(x == 0)[0]
array([1, 3, 5])
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How do I measure separate CPU core usage for a process?
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You can still do this in top. While top is running, press '1' on your keyboard, it will then ...
Are +0 and -0 the same?
Reading through the ECMAScript 5.1 specification , +0 and -0 are distinguished.
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What are bitwise operators?
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Since nobody has broached the subject of why these are useful:
I use bitwise operations a lot...