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PHP: merge two arrays while keeping keys instead of reindexing?
...
You can simply 'add' the arrays:
>> $a = array(1, 2, 3);
array (
0 => 1,
1 => 2,
2 => 3,
)
>> $b = array("a" => 1, "b" => 2, "c" => 3)
array (
'a' => 1,
'b' => 2,
'c' => 3,
)
>> $a + $b
array (
0 => 1,
1 => 2,
...
Finding the index of elements based on a condition using python list comprehension
...nstead of a list.
>>> import numpy
>>> a = numpy.array([1, 2, 3, 1, 2, 3])
>>> a
array([1, 2, 3, 1, 2, 3])
>>> numpy.where(a > 2)
(array([2, 5]),)
>>> a > 2
array([False, False, True, False, False, True], dtype=bool)
>>> a[numpy.where(a ...
What's the 'Ruby way' to iterate over two arrays at once
...
>> @budget = [ 100, 150, 25, 105 ]
=> [100, 150, 25, 105]
>> @actual = [ 120, 100, 50, 100 ]
=> [120, 100, 50, 100]
>> @budget.zip @actual
=> [[100, 120], [150, 100], [25, 50], [105, 100]]
>> @budget.zip(@actual...
Are list-comprehensions and functional functions faster than “for loops”?
...
154
The following are rough guidelines and educated guesses based on experience. You should timeit...
How to get subarray from array?
I have var ar = [1, 2, 3, 4, 5] and want some function getSubarray(array, fromIndex, toIndex) , that result of call getSubarray(ar, 1, 3) is new array [2, 3, 4] .
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What would cause an algorithm to have O(log n) complexity?
...ere are a few:
Repeatedly dividing by a constant
Take any number n; say, 16. How many times can you divide n by two before you get a number less than or equal to one? For 16, we have that
16 / 2 = 8
8 / 2 = 4
4 / 2 = 2
2 / 2 = 1
Notice that this ends up taking four steps to complete. Inte...
How to initialize an array in one step using Ruby?
...
192
You can use an array literal:
array = [ '1', '2', '3' ]
You can also use a range:
array = ...
Formatting Decimal places in R
I have a number, for example 1.128347132904321674821 that I would like to show as only two decimal places when output to screen (or written to a file). How does one do that?
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Single Line Nested For Loops
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172
The best source of information is the official Python tutorial on list comprehensions. List c...