(a ? b : c)

In python you can do this in three ways, the third way is only available in python 2.5 and up. It is essentially a ternary operator and doesn’t require any complicated hacks. In these lambda function examples I am using a as the conditional, b as the true option and c as the false option:

q=lambda a,b,c: (a and [b] or [c])[0]

This works due to the particular nature of and and or. The article is very good and goes in depth into the nature of and and or, specifically as to why this works. The reason that b and c are in brackets is because in some cases the b value can return False, but a list will always return True. Since we are returning a list we must reference the first element.

q=lambda a,b,c: (b,c)[not a]

In this instance we rely on the fact that True == 1 and False == 0. This is important because we are using a conditional to access an element of the tuple. If a is True then not a will be false, or 0, thus accessing the first element. Similarly if a is False then not a will be True, or 1, and this will access the second element.

q=lambda a,b,c: b if a else c

This simply returns b if a is true and c otherwise. Very self explanatory.

Here is an example of each form in action:

twoleg  = ["human", "kangaroo"]
fourleg = ["dog", "elephant"]
animals = ["human", "kangaroo", "dog", "elephant"]

print("\nMethod one:")
for c in animals:
    print "%s has %s legs"%(c, (c in twoleg and ["two"] or ["four"])[0])

print("\nMethod two:")
for c in animals:
    print "%s has %s legs"%(c, ("two", "four")[c not in twoleg])

print("\nPython 2.5+ only:")
for c in animals:
    print "%s has %s legs"%(c, "two" if c in twoleg else  "four")

Your server names will, of course, vary. Localhost is the machine you are currently on and, in my case, northisup.com is the server I’m SSHing into.

localhost$ ssh-keygen -t dsa
localhost$ cat ~/.ssh/id_dsa.pub | \
  ssh northisup.com 'cat >> ~/.ssh/authorized_keys; \
  chmod 644 ~/.ssh/authorized_keys; \
  cat ~/.ssh/authorized_keys'
localhost$ ssh username@northisup.com

If you are prompted for a password it should be the password entered in the first step.

This part:

chmod 644 ~/.ssh/authorized_keys

is the most common cause of problems, ssh requires authorized_keys not be group writable. Permissions are also important for the home directory on the server.

Now at this point you may be done, but if it is still asking for your key password (you will know because the password dialog is different from the standard ssh dialog) then you will have to set up an ssh-agent. I haven’t had to setup an ssh-agent in years; this is because many modern OSs like OS X and recent versions of Ubuntu have keychains that have properties indistinguishable from magic.

localhost$ ssh-agent code
localhost$ ssh-add ~/.ssh/id_dsa
localhost$ ssh username@northisup.com

This is effective only for your current shell. So if you open up a second instance of xterm you’ll have to do it again. Further more it doesn’t allow cron or other scripts, which frequently run in their own shell instances, to use passwordless ssh. To solve this we want to add the agent initalization to our .coderc file.

Edit ~/.bashrc and add the following at the end:

ssh_agent="$HOME/.ssh-agent.sh"
if [ -f $ssh_agent ] ; then
  source $ssh_agent > /dev/null
fi

Note that I pipe the output to /dev/null to stop the agent pid being echo’d which can break the pipe of some commands (sftp, for instance).

localhost$ ssh-agent > ~/.ssh-agent.sh

Either exit the shell and start a new one or

localhost$ source ~/.ssh_agent.sh
localhost$ ssh-add ~/.ssh/id_dsa
localhost$ ssh username@northisup.com

This time there should be no password!

While ssh-agent is running all your processes (including your cron jobs) shouldn’t need a password. However if ssh-agent dies or is killed things might go wrong since the old settings are left over.

#!/usr/bin/env python
# encoding: utf-8
"""
chart_example.py

Dynamic example of chart visualization

Created by Adam Hitchcock on 2009-05-05.
Copyright (c) 2009 __NorthIsUp__. All rights reserved.
"""

import sys
import os
import string
import subprocess
import cherrypy

body = """

"""

class DataTable():
	def __init__(self):
		"""columns [{'name':'aname', 'type':'JStype'}]"""

		self.columns = []
		self.values = []
		pass

	def render(self):
		s = """

		
		

"""
		return s + body

	def add_column(self, name, jstype):
		self.columns.append({'name':name, 'jstype':jstype})

	def add_value(self, row, column, value):
		"""docstring for add_value"""
		self.values.append({'row':row, 'column':column, 'value':value})

class chart_example(object):

	def index(self):
		d = DataTable()
		columns = [
		{'jstype':'date',	'name':'Date'},
		{'jstype':'number', 'name':'Sold Pencils'},
		{'jstype':'string', 'name':'title1'},
		{'jstype':'string', 'name':'text1'},
		{'jstype':'number', 'name':'Sold Pens'},
		{'jstype':'string', 'name':'title2'},
		{'jstype':'string', 'name':'text2'},
		]

		values = [
		[{'column':0, 'value':"new Date(2008, 1 ,1)"},
		{'column':1, 'value':"30000"},
		{'column':4, 'value':"40645"},],

		[{'column':0, 'value':"new Date(2008, 1 ,2)"},
		{'column':1, 'value':"14045"},
		{'column':4, 'value':"20374"},],

		[{'column':0, 'value':"new Date(2008, 1 ,3)"},
		{'column':1, 'value':"55022"},
		{'column':4, 'value':"50766"},],

		[{'column':0, 'value':"new Date(2008, 1 ,4)"},
		{'column':1, 'value':"75284"},
		{'column':4, 'value':"14334"},
		{'column':5, 'value':"'Out of Stock'"},
		{'column':6, 'value':"'Ran out of stock on pens at 4pm'"},],

		[{'column':0, 'value':"new Date(2008, 1 ,5)"},
		{'column':1, 'value':"41476"},
		{'column':2, 'value':"'Bought Pens'"},
		{'column':3, 'value':"'Bought 200k pens'"},
		{'column':4, 'value':"66467"},],

		[{'column':0, 'value':"new Date(2008, 1 ,6)"},
		{'column':1, 'value':"33322"},
		{'column':4, 'value':"39463"},
		{'column':2, 'value':"'Bought Pens2'"},
		{'column':3, 'value':"'Bought 200k pens2'"},
		{'column':4, 'value':"66467"},],

		[{'column':0, 'value':"new Date(2008, 1 ,7)"},
		{'column':1, 'value':"33322"},
		{'column':4, 'value':"39463"}]
		,]

		for c in columns:
			d.add_column(c['name'], c['jstype'])

		for vals, i in zip(values, range(len(values))):
			for v in vals:
				d.add_value(i, v['column'], v['value'])
		return d.render()
	index.exposed = True

class sub_wrapper(object):
	def renext(self, next):
		print next

	def doit(self, popenargs):
		result = subprocess.Popen(popenargs, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
		return result

cherrypy.config.update({'server.socket_host': '127.0.0.1', 'server.socket_port': 8080, })
cherrypy.quickstart(chart_example())

1) I like command line options.
2) I like to be able to run other command line programs and parse the output

Code after the break.

#!/usr/bin/env python
# encoding: utf-8
"""
${TM_NEW_FILE_BASENAME}.py

Created by ${TM_FULLNAME} on ${TM_DATE}.
Copyright (c) ${TM_YEAR} ${TM_ORGANIZATION_NAME}. All rights reserved.
"""

import os
import sys
import getopt
import subprocess

help_message = '''
The help message goes here.
'''

class Usage(Exception):
    def __init__(self, msg):
        self.msg = msg

def main(argv=None):
    if argv is None:
        argv = sys.argv
    try:
        try:
            opts, args = getopt.getopt(argv[1:], "ho:v", ["help", "output="])
        except getopt.error, msg:
            raise Usage(msg)

        # option processing
        for option, value in opts:
            if option == "-v":
                verbose = True
            if option in ("-h", "--help"):
                raise Usage(help_message)
            if option in ("-o", "--output"):
                output = value

    except Usage, err:
        print >> sys.stderr, sys.argv[0].split("/")[-1] + ": " + str(err.msg)
        print >> sys.stderr, "\t for help use --help"
        return 2

    def renext(next):
        print next

    def main():
        popenargs = []
        result = subprocess.Popen(popenargs, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        while 1:
            print dir(result)
            next = result.stdout.readline()
            if not next:
                break
            else:
                print next

if __name__ == "__main__":
    sys.exit(main())

Head Tracking for Desktop VR Displays using the WiiRemote

Just think about how awesome games like Call of Duty, Time Crisis, Metroid, and Metal Gear Solid would be. Even those boring targets floating in the air were exciting to watch.

12/20/08 President-elect Obama’s Weekly Address

From landing on the moon, to sequencing the human genome, to inventing the Internet, America has been the first to cross that new frontier because we had leaders who paved the way: leaders like President Kennedy, who inspired us to push the boundaries of the known world and achieve the impossible; leaders who not only invested in our scientists, but who respected the integrity of the scientific process,

…

Because the truth is that promoting science isn’t just about providing resources — it’s about protecting free and open inquiry. It’s about ensuring that facts and evidence are never twisted or obscured by politics or ideology. It’s about listening to what our scientists have to say, even when it’s inconvenient — especially when it’s inconvenient. Because the highest purpose of science is the search for knowledge, truth and a greater understanding of the world around us.

Obama has already proven his ability to tame the beast that is the World Wide Web, let’s see if he can be just as visionary elsewhere. Maybe it’s just me, but but does  anybody else find it ironic that we’re all so excited about science, even more so because of the Bush administration being so against it?

A member of the Pantheon (Poseiden?) getting due recognition for aiding our nation's founding.

Today Jim DeMinit (R-S.C.) lambasted the new visitor center (yes, this guy has time in this economic crisis to comment on that state of the new visitor center on Capital Hill) as “Left-leaning”, and “portray[s] the federal government as the fulfillment of human ambition and the answer to all of society’s problems.” DeMint suggests “This is a clear departure from acknowledging that Americans’ rights ‘are endowed by their Creator’ and stem from ‘a firm reliance on the protection of Divine Providence.’” Right, because it was God who co-sponsord the New Deal, and it was God who finished that hard work on the Union-Pacific rail road, and oh yeah, wasn’t it God who ended slavery? Listen to this guy:

“The Capitol Visitor Center is designed to tell the history and purpose of our nation’s Capitol, but it (1) fails to appropriately honor our religious heritage that has been critical to America’s success. While the Architect of the Capitol has pledged to include some references to faith, more needs to be done. You (2)cannot accurately tell the history of America or its Capitol by ignoring the religious heritage of our Founders and the generations since who relied on their faith for strength and guidance. The millions of visitors that will visit the CVC each year (3)should get a true portrayal of the motivations and inspirations of those who have served in Congress since its establishment.”

I noticed a few things about this statement, and you can refer to the numerated phrases in the quote.

(1). I don’t think he means our puritan heritage, and one must really ask why it would be appropriate to include a tribute to any deity on capital hill, thanking them for helping our country go from dream to reality. If anything, i assure you it overemphasizes it by replacing critical thought and hard work with devine intervention in some way.

(2) You can’t? Fun fact, Thomas Jefferson wrote his own verion of the Bible that takes out all references to God and any supernatural activity. I wonder if he thinks you could tell the story of America’s heritage by ignoring God. DeMint is one of these guys who thought the founders put Christmas in the constitution, that the pledge always had “under god” in it, and that our money always said “in god we trust”

(3) I think he means we need gigantic statues of John Locke, Rousseu, Hobbes, Weber, and host of others, rather some archaic “old” god that cares more for smiting non-believers that politcal theory. seriously, everything God decreed was plagiarized from the Code of Hamurabi anyway.When will we kick the Jesus freaks from our capitals?

"I'm Jim DeMint, and I believe that secular self determination doesn't exist. Vote for me"

“It’s so cool that FIJI is sponsoring an event like this. FIJI is my favorite water!”

-Kanye West

The global market for bottled water amounts to approximately $100 billion in sales annually and consists of an estimated 154 billion liters of fresh water. “The United States is the world’s leading consumer of bottled water, with Americans drinking 26 billion liters in 2004, or approximately one 8-ounce glass per person every day. Mexico has the second highest consumption, at 18 billion liters. China and Brazil follow, at close to 12 billion liters each. Ranking fifth and sixth in consumption are Italy and Germany, using just over 10 billion liters of bottled water each.”

This demand is driven by a variety of factors, many of which are the result of successful marketing campaigns by bottled water companies as well as intrinsic marketing advantages that present themselves during the regulatory process. It isn’t all that difficult to convince consumers that bottled water is something they need since water is a physiological necessity; humans need water to survive, but is the bottle necessary? “The Institute of Medicine advises that men consume roughly 3.0 liters (about 13 cups) of total beverages [water] a day and women consume 2.2 liters (about 9 cups) of total beverages [water] a day” There is also a perception that the water being consumed from bottled water is somehow more “pure” than tap water. The fact of the matter is that the EPA heavily regulates tap water and as a result the water is very clean. Bottled water on the other hand is not a public utility, and therefore isn’t bound to the same sort of regulatory scrutiny from the EPA. The Food and Drug Administration handles the regulation of bottled water, and those standards are much more relaxed.

Part of the purity perception problem with bottled water stems from the contrast in transparency of the EPA regulated tap water and the FDA regulated bottled water. Anyone can go to the EPA website and download extensive reports on the quality of tap water and see how their local water measures up to EPA standards. Because of the open access to information, when (in the rare occasion) a city fails to meet EPA standards (usually because a private corporation pollutes the water) it makes news around the country, and contributes to the purity bias of bottled water. The FDA only checks the quality of the bottled water once every three to five years, and the information is not as easily accessible. Furthermore, since the FDA requires a nutrition label on the back of every bottle, consumers can see what minerals have been added, helping bolster the illusion that bottled water has minerals that don’t exist in tap water and that consumption will lead to a healthier lifestyle.

Conspicuous consumption marketing tactics are used by bottled water manufactures to amplify to the purity bias. Conspicuous consumption is the idea that we buy certain products because we want others to see that we own them, like expensive cars, large houses, and other luxury goods. Fiji Water markets itself as a luxury water, proclaiming on their website, “all waters are not created equal.” The packaging of Fiji Water, the box-shaped bottle, suggests to the consumer that this product was made with a supreme technological craft that other bottles water manufactures don’t have. The right angles of the bottle are aesthetically pleasing, and they make the bottle feel less like garbage and more like a modernist decoration. The label is clear, with exotic plants and flowers displayed prominently and the water just visible behind creating a perception of exoticism. A quick glance at the bottle makes you feel like your looking at a small piece of paradise; a destination frequented by the affluent. If someone is seen with bottled water in hand, they appear as though they are on the go, and they look as though they have an active lifestyle that requires a higher degree of preparation than the average citizen. This is of course just a perception, but it is the result of conspicuous consumption. Finally, the founder of Fiji Water owns an exclusive resort on the island that celebrities have frequented for years. Part of the marketing strategy employed by Fiji Waters is to get the beverage in the hands of supermodels and superstars as often as possible, the lend star studded credit to the product. The goal is to make Fiji Water appear better than the rest.

Using the solar panel directly with my cell phone at WWDC 2008.

The solar panel is about the size of an iPod Touch. Via a suite of dongles that come with it you can plug this solar panel into just about any cell phone, mp3 player, or other small electronic devices that needs charging.

But what about those times I don’t find myself in the reach of sun light, I am, after all a programer and prefer the blue iridescent glow of the computer screen. This is where the Power Monkey Explorer’s rechargeable (weather proof) battery comes in. You can plug the solar panel into this, charge it up, and then use the juice whenever you need.

The single best part of the Power Monkey Explorer is that it eliminated four chargers I need to take with me when I travel.

The Power Monkey Explorer is a rugged device and I plan on taking it with me on all my future travels.

Charging the battery on a quick flight.