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How to reorder data.table columns (without copying)
...ta.table(a = 1:3, b = 3:1, c = runif(3))
x
# a b c
# [1,] 1 3 0.2880365
# [2,] 2 2 0.7785115
# [3,] 3 1 0.3297416
setcolorder(x, c("c", "b", "a"))
x
# c b a
# [1,] 0.2880365 3 1
# [2,] 0.7785115 2 2
# [3,] 0.3297416 1 3
From ?setcolorder:
In data.table parlance, all s...
css3 实现静态图片闪烁效果 - 更多技术 - 清泛网 - 专注C/C++及内核技术
... ease-in-out;
position: absolute;
}
@-webkit-keyframes start {
0%,30% {opacity: 0;-webkit-transform: translate(0,0);}
60% {opacity: 1;-webkit-transform: translate(0,0);}
100% {opacity: 1;-webkit-transform: translate(0,0);}
}
@-moz-keyframes start {
0%,30% {opacity: 0;-mo...
How to show all shared libraries used by executables in Linux?
...-e '/^[^\t]/ d' \
| sed -e 's/\t//' \
| sed -e 's/.*=..//' \
| sed -e 's/ (0.*)//' \
| sort \
| uniq -c \
| sort -n
Change "/bin" above to "/" to search all directories.
Output (for just the /bin directory) will look something like this:
1 /lib64/libexpat.so.0
1 /lib64/libgcc_s.so.1
1 /lib...
How to validate an e-mail address in swift?
...ValidEmail(_ email: String) -> Bool {
let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"
let emailPred = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
return emailPred.evaluate(with: email)
}
for versions of Swift earlier than 3.0:
func isValidEmail(e...
Delete the first three rows of a dataframe in pandas
... |
edited Oct 17 '18 at 1:06
Acumenus
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answered...
How to convert a Binary String to a base 10 integer in Java
...ithout leading zeroes) that I want to convert to their corresponding base 10 numbers. Consider:
9 Answers
...
How do I get a human-readable file size in bytes abbreviation using .NET?
...MB", "GB", "TB" };
double len = new FileInfo(filename).Length;
int order = 0;
while (len >= 1024 && order < sizes.Length - 1) {
order++;
len = len/1024;
}
// Adjust the format string to your preferences. For example "{0:0.#}{1}" would
// show a single decimal place, and no spa...
How do I add 1 day to an NSDate?
...
720
Swift 5.0 :
var dayComponent = DateComponents()
dayComponent.day = 1 // For removing...
How to add a new row to an empty numpy array
...
The way to "start" the array that you want is:
arr = np.empty((0,3), int)
Which is an empty array but it has the proper dimensionality.
>>> arr
array([], shape=(0, 3), dtype=int64)
Then be sure to append along axis 0:
arr = np.append(arr, np.array([[1,2,3]]), axis=0)
arr =...
++someVariable vs. someVariable++ in JavaScript
...
250
Same as in other languages:
++x (pre-increment) means "increment the variable; the value of th...