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What makes Lisp macros so special?
...le syntax 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 ...
Convert data.frame column format from character to factor
...
201
Hi welcome to the world of R.
mtcars #look at this built in data set
str(mtcars) #allows you ...
A list of indices in MongoDB?
...
answered May 7 '10 at 22:52
mdirolfmdirolf
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...
PostgreSQL Connection URL
...ser:secret@localhost
postgresql://other@localhost/otherdb?connect_timeout=10&application_name=myapp
postgresql://localhost/mydb?user=other&password=secret
share
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...
How Many Seconds Between Two Dates?
...ger values meaning the day of the month.
var t1 = new Date(YYYY, MM, DD, 0, 0, 0, 0);
var t2 = new Date(ZZZZ, NN, EE, 0, 0, 0, 0);
var dif = t1.getTime() - t2.getTime();
var Seconds_from_T1_to_T2 = dif / 1000;
var Seconds_Between_Dates = Math.abs(Seconds_from_T1_to_T2);
A handy source for futur...
Convert list to array in Java [duplicate]
...
1103
Either:
Foo[] array = list.toArray(new Foo[0]);
or:
Foo[] array = new Foo[list.size()];
lis...
Strange \n in base64 encoded string in Ruby
...at confusing, the b64encode method is supposed to add a newline for every 60th character, and the example for the encode64 method is actually using the b64encode method.
It seems the pack("m") method for the Array class used by encode64 also adds the newlines. I would consider it a design bug that ...
How do I delete a fixed number of rows with sorting in PostgreSQL?
...d IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly, a row's ctid will change if it is updated or moved by VACUUM FU...
Download file from web in Python 3
...
+50
If you want to obtain the contents of a web page into a variable, just read the response of urllib.request.urlopen:
import urllib.requ...
Can you run GUI applications in a Docker container?
...n made with this Dockerfile:
# Firefox over VNC
#
# VERSION 0.1
# DOCKER-VERSION 0.2
FROM ubuntu:12.04
# Make sure the package repository is up to date
RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list
RUN apt-get updat...