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How to map and remove nil values in Ruby
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Ruby 2.7 is introducing filter_map for this exact purpose. It's idiomatic and performant, and I'd expect it to become the norm very soon.
For example:
numbers = [1, 2, 5, 8, 10, 13]
enum.filter_map { |i| i * 2 if i.even? }
# => [4, 16, 20]
In your case, as the block evaluates to falsey, simp...
Draw on HTML5 Canvas using a mouse
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I changed canvas.offsetLeft; and canvas.offsetTop; with canvas.getBoundingClientRect().left; and canvas.getBoundingClientRect().top; respectively to fix the scrolling problem.
– KWILLIAMS
Nov 15 '17 at 19:27
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Difference between Visibility.Collapsed and Visibility.Hidden
What are differences between Visibility.Collapsed and Visibility.Hidden in WPF?
3 Answers
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Understanding keystore, certificates and alias
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The keystore file generated by Keytool stores pairs of private and public keys. Each pair or entry stored in the keystore is refered by a unique alias. In brief:
Keystore entry = private + public key
pair = identified by an alias
The keystore protects each private key with its in...
Should an Enum start with a 0 or a 1?
...ag enum values of zero unless the value represents "all flags are cleared" and is named appropriately, as prescribed by the next guideline.
✔️ DO name the zero value of flag enums None. For a flag enum, the value must always mean "all flags are cleared."
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What encoding/code page is cmd.exe using?
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Yes, it’s frustrating—sometimes type and other programs
print gibberish, and sometimes they do not.
First of all, Unicode characters will only display if the
current console font contains the characters. So use
a TrueType font like Lucida Console instead of the...
Numpy `logical_or` for more than two arguments
...arrays? (The same question could be asked with regard to Numpy's logical_and and obtaining the intersection of more than two arrays.)
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Converting file size in bytes to human-readable string
...nary, so to express 1551859712 as ~1.4GiB would be correct.
On the other hand, hard disk manufacturers like to use decimal, so they would call it ~1.6GB.
And just to be confusing, floppy disks use a mixture of the two systems - their 1MB is actually 1024000 bytes.
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How to run only one task in ansible playbook?
... part of the configuration without running the whole playbook.
Both plays and tasks support a “tags:” attribute for this reason.
Example:
tasks:
- yum: name={{ item }} state=installed
with_items:
- httpd
- memcached
tags:
- packages
- template:...
How can I check if an ip is in a network in Python?
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This article shows you can do it with socket and struct modules without too much extra effort. I added a little to the article as follows:
import socket,struct
def makeMask(n):
"return a mask of n bits as a long integer"
return (2L<<n-1) - 1
def dotted...