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Check whether number is even or odd
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204
You can use the modulus operator, but that can be slow. If it's an integer, you can do:
if ( (...
Relative frequencies / proportions with dplyr
...n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That makes ...
How do I get the real .height() of a overflow: hidden or overflow: scroll div?
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Use the .scrollHeight property of the DOM node: $('#your_div')[0].scrollHeight
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How to create an array containing 1…N
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409
If I get what you are after, you want an array of numbers 1..n that you can later loop through....
What does value & 0xff do in Java?
... = value;
then result would end up with the value ff ff ff fe instead of 00 00 00 fe. A further subtlety is that the & is defined to operate only on int values1, so what happens is:
value is promoted to an int (ff ff ff fe).
0xff is an int literal (00 00 00 ff).
The & is applied to yield...
Ruby: Merging variables in to a string
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answered Feb 16 '09 at 21:42
Mike WoodhouseMike Woodhouse
47.6k1212 gold badges8585 silver badges123123 bronze badges
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Finding the max value of an attribute in an array of objects
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808
To find the maximum y value of the objects in array:
Math.max.apply(Math, array.map(function(o...
Concatenating two one-dimensional NumPy arrays
...ents.
From the NumPy documentation:
numpy.concatenate((a1, a2, ...), axis=0)
Join a sequence of arrays together.
It was trying to interpret your b as the axis parameter, which is why it complained it couldn't convert it into a scalar.
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Format output string, right alignment
...r.format syntax:
line_new = '{:>12} {:>12} {:>12}'.format(word[0], word[1], word[2])
And here's how to do it using the old % syntax (useful for older versions of Python that don't support str.format):
line_new = '%12s %12s %12s' % (word[0], word[1], word[2])
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How do I set the rounded corner radius of a color drawable using xml?
... a white background, black border and rounded corners:
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#ffffffff"/>
<stroke android:width="3dp"
android:color="...