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Painless way to install a new version of R?
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edited May 8 '19 at 2:46
Gregor Thomas
91.9k1515 gold badges126126 silver badges235235 bronze badges
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What makes Lisp macros so special?
...for a common case. The line
divisibleByTwo = [x for x in range(10) if x % 2 == 0]
yields a list containing all even numbers between 0 and 9. Back in the Python 1.5 days there was no such syntax; you'd use something more like this:
divisibleByTwo = []
for x in range( 10 ):
if x % 2 == 0:
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How do I determine the target architecture of static library (.a) on Mac OS X?
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244
Another option is lipo; its output is brief and more readable than otool's.
An example:
% li...
How does Python manage int and long?
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126
int and long were "unified" a few versions back. Before that it was possible to overflow an int...
Insert, on duplicate update in PostgreSQL?
...ing syntax (similar to MySQL)
INSERT INTO the_table (id, column_1, column_2)
VALUES (1, 'A', 'X'), (2, 'B', 'Y'), (3, 'C', 'Z')
ON CONFLICT (id) DO UPDATE
SET column_1 = excluded.column_1,
column_2 = excluded.column_2;
Searching postgresql's email group archives for "upsert" leads to...
How to import multiple .csv files at once?
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274
Something like the following should result in each data frame as a separate element in a singl...
How to draw border around a UILabel?
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265
You can set label's border via its underlying CALayer property:
#import <QuartzCore/Quartz...
How to change plot background color?
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242
Use the set_facecolor(color) method of the axes object, which you've created one of the follow...
How to Sign an Already Compiled Apk
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293
create a key using
keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -k...
What is the fastest or most elegant way to compute a set difference using Javascript arrays?
...if don't know if this is most effective, but perhaps the shortest
A = [1, 2, 3, 4];
B = [1, 3, 4, 7];
diff = A.filter(function(x) { return B.indexOf(x) < 0 })
console.log(diff);
Updated to ES6:
A = [1, 2, 3, 4];
B = [1, 3, 4, 7];
diff = A.filter(x => !B.includes(x) );
console.log(diff)...