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What does the “map” method do in Ruby?
...e from the block (the original object is unchanged unless you use map!):
[1, 2, 3].map { |n| n * n } #=> [1, 4, 9]
Array and Range are enumerable types. map with a block returns an Array. map! mutates the original array.
Where is this helpful, and what is the difference between map! and each...
How to add leading zeros?
...of digits to begin with, so let's try a harder example of making powers of 10 width 8 too.
anim <- 25499:25504
x <- 10 ^ (0:5)
paste (and it's variant paste0) are often the first string manipulation functions that you come across. They aren't really designed for manipulating numbers, but...
Why is a round-trip conversion via a string not safe for a double?
...
178
I found the bug.
.NET does the following in clr\src\vm\comnumber.cpp:
DoubleToNumber(value, ...
How to check Django version
...
691
Django 1.5 supports Python 2.6.5 and later.
If you're under Linux and want to check the Python ...
How random is JavaScript's Math.random?
...
183
Given numbers between 1 and 100.
9 have 1 digit (1-9)
90 have 2 digits (10-99)
1 has 3 digi...
How do I profile memory usage in Python?
...
123
This one has been answered already here: Python memory profiler
Basically you do something li...
Jasmine.js comparing arrays
...n() {
it('passes if arrays are equal', function() {
var arr = [1, 2, 3];
expect(arr).toEqual([1, 2, 3]);
});
});
Just for information:
toBe() versus toEqual(): toEqual() checks equivalence. toBe(), on the
other hand, makes sure that they're the exact same object.
...
Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash
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166
First, note that this behavior applies to any default value that is subsequently mutated (e.g....
Numbering rows within groups in a data frame
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edited Mar 14 '17 at 22:06
Frank
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Is there a standardized method to swap two variables in Python?
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401
Python evaluates expressions from left to right. Notice that while
evaluating an assignment...