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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 ...
Is there any boolean type in Oracle databases?
...read on asktom. From recommending CHAR(1) 'Y'/'N' they switch to NUMBER(1) 0/1 when someone points out that 'Y'/'N' depends on the English language, while e.g. German programmers might use 'J'/'N' instead.
The worst thing is that they defend this stupid decision just like they defend the ''=NULL st...
How do I read / convert an InputStream into a String in Java?
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edited May 21 '18 at 13:09
Marko Zajc
14811 silver badge1313 bronze badges
answered Nov 21 '08 at 16:5...
What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?
...
300
Your first port of call should be the documentation which explains it reasonably clearly:
T...
Python, Matplotlib, subplot: How to set the axis range?
How can I set the y axis range of the second subplot to e.g. [0,1000] ?
The FFT plot of my data (a column in a text file) results in a (inf.?) spike so that the actual data is not visible.
...
Accessing localhost:port from Android emulator
...
420
You can access your host machine with the IP address "10.0.2.2".
This has been designed in thi...
Check if an array is empty or exists
...
if (typeof image_array !== 'undefined' && image_array.length > 0) {
// the array is defined and has at least one element
}
Your problem may be happening due to a mix of implicit global variables and variable hoisting. Make sure you use var whenever declaring a variable:
<?php e...
How to wait in bash for several subprocesses to finish and return exit code !=0 when any subprocess
...ral subprocesses spawned from that script to finish and return exit code !=0 when any of the subprocesses ends with code !=0 ?
...
Regex to validate password strength
...itive look ahead assertions:
^(?=.*[A-Z].*[A-Z])(?=.*[!@#$&*])(?=.*[0-9].*[0-9])(?=.*[a-z].*[a-z].*[a-z]).{8}$
Rubular link
Explanation:
^ Start anchor
(?=.*[A-Z].*[A-Z]) Ensure string has two uppercase letters.
(?=.*[!@#$&*]) Ensure string ha...
Convert string with commas to array
... JSON.parse("[" + string + "]");
This gives you an Array of numbers.
[0, 1]
If you use .split(), you'll end up with an Array of strings.
["0", "1"]
Just be aware that JSON.parse will limit you to the supported data types. If you need values like undefined or functions, you'd need to use ...