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Select multiple columns in data.table by their numeric indices
... all just work:
library(data.table)
dt <- data.table(a = 1, b = 2, c = 3)
# select single column by index
dt[, 2]
# b
# 1: 2
# select multiple columns by index
dt[, 2:3]
# b c
# 1: 2 3
# select single column by name
dt[, "a"]
# a
# 1: 1
# select multiple columns by name
dt[, c("a", ...
regex to match a single character that is anything but a space
...
263
The following should suffice:
[^ ]
If you want to expand that to anything but white-space (li...
Where does this come from: -*- coding: utf-8 -*-
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This way of specifying the encoding of a Python file comes from PEP 0263 - Defining Python Source Code Encodings.
It is also recognized by GNU Emacs (see Python Language Reference, 2.1.4 Encoding declarations), though I don't know if it was the first program to use that syntax.
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How do I decode a base64 encoded string?
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answered Aug 20 '11 at 21:37
Matthew AbbottMatthew Abbott
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Convert UNIX epoch to Date object
...s integers representing the number of seconds since the UNIX epoch (e.g. 1352068320 ), but Date objects seem more appropriate for plotting. How can I do the conversion?
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Change values while iterating
...e.
This behavior is demonstrated by the following code:
x := make([]int, 3)
x[0], x[1], x[2] = 1, 2, 3
for i, val := range x {
println(&x[i], "vs.", &val)
}
The code prints you completely different memory locations for the value from range and the actual
value in the slice:
0xf8...
Fastest way to convert an iterator to a list
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350
list(your_iterator)
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Static classes and methods in coffeescript
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mu is too shortmu is too short
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How to pass macro definition from “make” command line arguments (-D) to C source code?
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ouahouah
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