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Accessing members of items in a JSONArray with Java
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edited Nov 9 '18 at 23:53
idewz
544 bronze badges
answered Oct 14 '09 at 20:32
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Django dynamic model fields
...for faster queries.
– GDorn
Mar 1 '15 at 6:10
1
Updated today to note Django's adoption of HStore...
Apply a function to every row of a matrix or a data frame
..., byrow=TRUE)
R> M
[,1] [,2]
[1,] 1 2
[2,] 3 4
[3,] 5 6
R> apply(M, 1, function(x) 2*x[1]+x[2])
[1] 4 10 16
R>
This takes a matrix and applies a (silly) function to each row. You pass extra arguments to the function as fourth, fifth, ... arguments to apply().
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Scala: Abstract types vs generics
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257
You have a good point of view on this issue here:
The Purpose of Scala's Type System
A Conve...
What is Ember RunLoop and how does it work?
...: https://machty.s3.amazonaws.com/ember-run-loop-visual/index.html
Update 5/9/2013: all the basic concepts below are still up to date, but as of this commit, the Ember Run Loop implementation has been split off into a separate library called backburner.js, with some very minor API differences.
Fir...
Remove all the elements that occur in one list from another
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526
Python has a language feature called List Comprehensions that is perfectly suited to making th...
load and execute order of scripts
...synchronously in Opera and pre-4.0 Firefox.
The relevant part of the HTML5 spec (for newer compliant browsers) is here. There is a lot written in there about async behavior. Obviously, this spec doesn't apply to older browsers (or mal-conforming browsers) whose behavior you would probably have t...
Python csv string to array
... StringIO
import csv
scsv = """text,with,Polish,non-Latin,letters
1,2,3,4,5,6
a,b,c,d,e,f
gęś,zółty,wąż,idzie,wąską,dróżką,
"""
f = StringIO(scsv)
reader = csv.reader(f, delimiter=',')
for row in reader:
print('\t'.join(row))
simpler version with split() on newlines:
reader = csv...
How useful/important is REST HATEOAS ( maturity level 3)?
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5 Answers
5
Active
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Determine the data types of a data frame's columns
...is makes the example exactly reproducible
my.data <- data.frame(y=rnorm(5),
x1=c(1:5),
x2=c(TRUE, TRUE, FALSE, FALSE, FALSE),
X3=letters[1:5])
@Wilmer E Henao H's solution is very streamlined:
sapply(my.data, class)
...