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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...
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] .
...
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...
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?
...
Single Line Nested For Loops
...
172
The best source of information is the official Python tutorial on list comprehensions. List c...
App Inventor 2 数学代码块 · App Inventor 2 中文网
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案例：指定将二进制的某一位(Bit)改为1
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