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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...
Get loop count inside a Python FOR loop
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605
The pythonic way is to use enumerate:
for idx,item in enumerate(list):
...
How to use the “required” attribute with a “radio” input field
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edited May 7 at 10:36
answered Nov 27 '11 at 18:31
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Why do enum permissions often have 0, 1, 2, 4 values?
Why are people always using enum values like 0, 1, 2, 4, 8 and not 0, 1, 2, 3, 4 ?
7 Answers
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Java: int array initializes with nonzero elements
... bug will be fixed.
There is only advice at the moment: do not use JDK1.7.0_04 or later if you depend on JLS for newly declared arrays.
Update at October 5:
In the new Build 10 of the JDK 7u10 (early access) released at October 04, 2012, this bug was fixed at least for Linux OS (I did not test fo...
How to format a number 0..9 to display with 2 digits (it's NOT a date)
I'd like to always show a number under 100 with 2 digits (example: 03, 05, 15...)
5 Answers
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How can I sort a dictionary by key?
What would be a nice way to go from {2:3, 1:89, 4:5, 3:0} to {1:89, 2:3, 3:0, 4:5} ?
I checked some posts but they all use the "sorted" operator that returns tuples.
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Performance difference for control structures 'for' and 'foreach' in C#
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130
Well, it partly depends on the exact type of list. It will also depend on the exact CLR you're u...
Total memory used by Python process?
...l with psutil 5.6.3, the last line should be
print(process.memory_info()[0])
instead (there was a change in the API).
Note: do pip install psutil if it is not installed yet.
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How do I get the current date in JavaScript?
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var today = new Date();
var dd = String(today.getDate()).padStart(2, '0');
var mm = String(today.getMonth() + 1).padStart(2, '0'); //January is 0!
var yyyy = today.getFullYear();
today = mm + '/' + dd + '/' + yyyy;
document.write(today);
This will give you today's date in the forma...