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Why are hexadecimal numbers prefixed with 0x?
...nicely divisible by 3 = log2(8).
The BCPL language used the syntax 8 1234 for octal numbers. When Ken Thompson created B from BCPL, he used the 0 prefix instead. This is great because
an integer constant now always consists of a single token,
the parser can still tell right away it's got a consta...
Returning a boolean from a Bash function
...
Use 0 for true and 1 for false.
Sample:
#!/bin/bash
isdirectory() {
if [ -d "$1" ]
then
# 0 = true
return 0
else
# 1 = false
return 1
fi
}
if isdirectory $1; then echo "is directory"; else echo "nopes"...
C# List of objects, how do I get the sum of a property
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Is this quicker than foreach out of interest?
– Coops
Feb 4 '13 at 14:08
4
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Shell equality operators (=, ==, -eq)
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It's the other way around: = and == are for string comparisons, -eq is for numeric ones. -eq is in the same family as -lt, -le, -gt, -ge, and -ne, if that helps you remember which is which.
== is a bash-ism, by the way. It's better to use the POSIX =. In bash the ...
JavaScript get window X/Y position for scroll
...ow's position (relative to the total page width/height) so I can use it to force a scroll from one section to another. However, there seems to be a tremendous amount of options when it comes to guessing which object holds the true X/Y for your browser.
...
Never seen before C++ for loop
I was converting a C++ algorithm to C#.
I came across this for loop:
12 Answers
12
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How can I get a list of locally installed Python modules?
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Solution
Do not use with pip > 10.0!
My 50 cents for getting a pip freeze-like list from a Python script:
import pip
installed_packages = pip.get_installed_distributions()
installed_packages_list = sorted(["%s==%s" % (i.key, i.version)
for i in installed_packages])
pr...
Moving UITabBarItem Image down?
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Try adjusting tabBarItem's imageInsets (for moving the icon image) and setting the controllers title to nil (so no title is displayed). Put something like this to -init or -viewDidLoad method in view controller:
Objective-C
self.tabBarItem.imageInsets = UIEdgeIns...
Looping through array and removing items, without breaking for loop
I have the following for loop, and when I use splice() to remove an item, I then get that 'seconds' is undefined. I could check if it's undefined, but I feel there's probably a more elegant way to do this. The desire is to simply delete an item and keep on going.
...
C++: Rounding up to the nearest multiple of a number
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This works for positive numbers, not sure about negative. It only uses integer math.
int roundUp(int numToRound, int multiple)
{
if (multiple == 0)
return numToRound;
int remainder = numToRound % multiple;
if (rema...