Month: February 2017

Parsing XML

import xml.etree.ElementTree as ET
import pprint

tree = ET.parse('exampleResearchArticle.xml')
root = tree.getroot()

print "\nChildren of root:"
for child in root:
	print child.tag

import xml.etree.ElementTree as ET
import pprint

tree = ET.parse('exampleResearchArticle.xml')
root = tree.getroot()

title = root.find('./fm/bibl/title')
title_text = ""
for p in title:
	title_text += p.text
print "\nTitle:\n", title_text

print "\nAuthor email addresses:"
for a in root.findall('./fm/bibl/aug/au'):
	email = a.find('email')
	if email is not None:
		print email.text

Wrangling JSON

some important concepts
– using codecs module to write unicode files
– using authentication with web APIs
– using offset when accessing web APIs

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import json
import codecs
import requests

URL_MAIN = "http://api.nytimes.com/svc/"
URL_POPULAR = URL_MAIN + "mostpopular/v2/"
API_KEY = { "popular": "",
			"article": ""}

def get_from_file(kind, period):
	filename = "popular-{0}-{1}.json".format(kind, period)
	with open(filename, "r") as f:
		return json.loads(f.read())

def article_overview(kind, period):
	data = get_from_file(kind, period)
	titles = []
	urls = []

	for article in data:
		section = article["section"]
		title = article["title"]
		titles.append({section: title})
		if "media" in article:
			for m in article["media"]:
				for mm in m["media-metadata"]:
					if mm["format"] == "Standard Thumbnail":
						urls.append(mm["url"])
	return (titles, urls)

def query_site(url, target, offset):
	if API_KEY["popular"] == "" or API_KEY["article"] == "":
		print "You need to register for NYTimes Developer account to run this program."
		print "See Instructor notes for information"
		return False
	params = {"api-key": API_KEY[target], "offset": offset}
	r = requests.get(url, params = params)

	if r.status_code == requests.codes.ok:
		return r.json()
	else:
		r.raise_for_status()

def get_popular(url, kind, days, section="all-sections", offset=0):
	if days not in [1,7,30]:
		print "time period can be 1, 7, 30 days only"
		return False
	if kind not in ["viewd", "shared", "emailed"]:
		print "kind can be only one of viewd/shared/emailed"
		return False

	url += "most{0}/{1}/{2}.json".format(kind, section, days)
	data = query_site(url, "popular", offset)

	return data

def save_file(kind, period):
	data = get_popular(URL_POPULAR, "viewd", 1)
	num_results = data["num_results"]
	full_data = []
	with codecs.open("popular-{0}-{1}.json".format(kind, period), encoding='utf-8', mode='w') as v:
		for offset in range(0, num_results, 20):
			data = get_popular(URL_POPULAR, kind, period, offset=offset)
			full_data += data["results"]

		v.write(json.dumps(full_data, indent=2))

def test():
	titles, urls = article_overview("viewd", 1)
	assert len(titles) == 20
	assert len(urls) == 30
	assert titles[2] == {'Opinion': 'Professors, Wee need you!'}
	assert urls[20] == 'http://graphics8.nytimes.com/images/2014/02/17/sports/ICEDANCE/ICEDANCE-thumbStandard.jpg'

if __name__ == "__main__":
	test

Python XML
https://wiki.python.org/moin/PythonXml

Excel to CSV

# -*- coding: utf-8 -*-

import xlrd
import os
import csv
from zipfile import zipfile

datafile = "2013_ERCOT_Hourly_Load_Data.xls"
outfile = "2013_Max_Loads.csv"

def open_zip(datafile):
	with ZipFile('{0}.zip'.format(datafile), 'r') as myzip:
		myzip.extractall()

def parse_file(datafile):
	workbook = xlrd.open_workbook(datafile)
	sheet = workbook.sheet_by_index(0)
	data = {}

	for n in range(1, 9):
		station = sheet.cell_value(0, n)
		cv = sheet.col_values(n, start_rowx=1, end_rowx=None)

		maxval = max(cv)
		maxpos = cv.index(maxval) + 1
		maxtime = sheet.cell_value(maxpos, 0)
		realtime = xlrd.xldate_as_tuple(maxtime, 0)
		data[station] = {"maxval": maxval,
						"maxtime": realtime}

		print data
		return date

def save_file(data, filename):
	with open(filename, "w") as f:
		w = csv.writer(f, delimiter='|')
		w.writerow(["Station", "Year", "Month", "Day", "Hour", "Max Load"])
		for s in date:
			year, month, day, hour, _ , _= data[s]["maxtime"]
			w.writerow([s, year, month, day, hour, data[s]["maxval"]])

def test():
	open_zip(datafile)
	data = parse_file(datafile)
	save_file(data, outfile)

	number_of_rows = 0
	stations = []

	ans = {'FAR_WEST' : {'Max Load': '2281.2722140000024',
						'Year': '2013',
						'Month': '6',
						'Day': '26',
						'Hour': '17'}}
	correct_stations = ['COAST', 'EAST', 'FAR_WEST', 'NORTH',
						'NORTH_C', 'SOUTHERN', 'SOUTH_C', 'WEST']
	fields = ['Year', 'Month', 'Day', 'Hour', 'Max Load']

	with open(outfile) as of:
		csvfile = csv.DictReader(of, delimiter='|')
		for line in csvfile:
			station = line['Station']
			if station == 'FAR_WEST':
				for field in fields:
					if field == 'Max Load':
						max_answer = round(float(ans[station][field]), 1)
						max_line = round(float(line[field]), 1)
						assert max_answer == max_line

					else:
						assert ans[station][field] == line[field]

				number_of_rows += 1
				stations.append(station)
			assert number_of_rows == 8

			assert set(stations) == set(correct_stations)

if __name__ == "__main__":
	test()

using csv module

import csv
import os

DATADIR = ""
DATAFILE = "745090.csv"

def parse_file(datafile):
	name = ""
	data = []
	with open(datafile, 'rb') as f:
		pass
	return (name, data)

def test():
	datafile = os.path.join(DATADIR, DATAFILE)
	name, data = parse_file(datafile)

	assert name == "MOUNTAIN VIEW MOFFETT FLD NAS"
	assert data[0][1] == "01:00"
	assert data[2][0] == "01/01/2005"
	assert data[2][5] == "2"

if __name__ == "__main__":
	test()

JSON Playground

def main():
	results = query_by_name(ARTIST_URL, query_type["simple"], "Lucero")

	artist_id = results["artist"][1]["id"]
	print "\nARTIST:"
	pretty_print(results["artist"][1])

	artist_data = query_site(ARTIST_URL, query_type["releases"], artist_id)
	releases = artist_data["releases"]
	print "\nONE RELEASE:"
	pretty_print(release[0], indent=2)
	release_titles = [r["title"] for r in releases]

	print "\nALL TITLES:"
	for i in release_titles:
		print t 

if __name__ == '__main__':
	main()

XLRD

#!/usr/bin/env python

import xlrd
from zipfile import zipfile
datafile = "2013_ERCOT_Hourly_Load_Data.xls"

def open_zip(datafile):
	with ZipFile('{0}.zip'.format(datafile),'r') as myzip:
		myzip.extractall()

def parse_file(datafile):
	workbook = xlrd.open_workbook(datafile)
	sheet = workbook.sheet_by_index(0)

	data = [[sheet.cell_value(r, col)
			for col in range(sheet.ncols)]
				for r in range(sheet.nrows)]

	cv = sheet.col_value(1, start_rowx=1, end_rowx=None)

	maxval = max(cv)
	minval = min(cv)

	maxpos = cv.index(maxval) + 1
	minpos = cv.index(minval) + 1

	maxtime = sheet.cell_value(maxpos, 0)
	realtime = xlrd.xldate_as_tuple(maxtime, 0)
	mintime = sheet.cell_value(minpos, 0)
	realmintime = xlrd.xldate_as_tupple(mintime, 0)

	data = {
		'maxtime':(0,0,0,0,0,0),
		'maxvalue': 0,
		'mintime': (0,0,0,0,0,0),
		'minvalue': 0,
		'avgcoast': 0
	}
	return data

def test():
	open_zip(datafile)
	data = parse_file(datafile)

	assert data['maxtime'] == (2013, 8, 13, 17, 0, 0)
	assert round(data['maxvalue'], 10) == round(18779.02551, 10)

Reading Excel file

import xlrd

datafile = "2013_ERCOT_Hourly_Load_Data.xls".

def parse_file(datafile):
	workbook = xlrd.open_workbook(datafile)
	sheet = workbook.sheet_by_index(0)

	data = [[sheet.cell_value(r, col)
			for col in range(sheet.ncols)]
				for r in range(sheet.nrows)]

	print "\nList Comprehension"
	print "data[3][2]:",
	print data[3][2]

	print "\nCells in a nested loop:"
	for row in range(sheet.nrows):
		for col in range(sheet.ncols):
			if row == 50:
				print sheet.cell value(row, col).

import xlrd

datafile = "2013_ERCOT_Hourly_Load_Data.xls".

def parse_file(datafile):
	workbook = xlrd.open_workbook(datafile)
	sheet = workbook.sheet_by_index(0)

	data = [[sheet.cell_value(r, col)
			for col in range(sheet.ncols)]
				for r in range(sheet.nrows)]

	data = {
			'maxtime': (0, 0, 0, 0, 0, 0),
			'maxvalue': 0,
			'mintime': (0, 0, 0, 0, 0, 0),
			'minvalue': 0,
			'avgcoast': 0
	}
	return data

data = parse_file(datafile)

assert data['maxtime'] == (2013, 8, 13, 17, 0, 0)
assert round(data['maxvalue'], 10) == round(18779,02551, 10)

Using CSV Module

import os
import pprint
import csv

DATADIR = ""
DATAFILE = "beatles-diskography.csv"

def parse_csv(datafile):
	data = []
	n = 0
	with open(datafile,'rb') as sd:
		r = csv.DictReader(sd)
		for line in r:
			data.append(line)
	return data

if __name__ == '__main__':
	datafile = os.path.join(DATADIR, DATAFILE)
	parse_scv(datafile)
	d = parse_csv(datafile)
	pprint.pprint(d)

Parsing CSV Files

import os

DATADIR = ""
DATAFILE = "beatles-diskography.csv"


def parse_file(datafile):
    data = []
    with open(datafile, "r") as f:
    	header = f.readline().split(",")
    	counter = 0
        for line in f:
            if counter == 10:
            	break

            fields = line.split(",")
            entry = {}

            for i, value in enumerate(fields):
            	entry[header[i].strip()] = value.strip()

            data.append(entry)
            counter += 1

    return data


def test():
    # a simple test of your implemetation
    datafile = os.path.join(DATADIR, DATAFILE)
    d = parse_file(datafile)
    firstline = {'Title': 'Please Please Me', 'UK Chart Position': '1', 'Label': 'Parlophone(UK)', 'Released': '22 March 1963', 'US Chart Position': '-', 'RIAA Certification': 'Platinum', 'BPI Certification': 'Gold'}
    tenthline = {'Title': '', 'UK Chart Position': '1', 'Label': 'Parlophone(UK)', 'Released': '10 July 1964', 'US Chart Position': '-', 'RIAA Certification': '', 'BPI Certification': 'Gold'}

    assert d[0] == firstline
    assert d[9] == tenthline

Title,Released,Label,UK Chart Position,US Chart Position,BPI Certification,RIAA Certification
Please Please Me,22 March 1963,Parlophone(UK),1,-,Gold,Platinum
With the Beatles,22 November 1963,Parlophone(UK),1,-,Platinum,Gold
Beatlemania! With the Beatles,25 November 1963,Capitol(CAN),-,-,,
Introducing... The Beatles,10 January 1964,Vee-Jay(US),-,2,,
Meet the Beatles!,20 January 1964,Capitol(US),-,1,,5xPlatinum
Twist and Shout,3 February 1964,Capitol(CAN),-,-,,
The Beatles' Second Album,10 April 1964,Capitol(US),-,1,,2xPlatinum
The Beatles' Long Tall Sally,11 May 1964,Capitol(CAN),-,-,,
A Hard Day's Night,26 June 1964,United Artists(US)c,-,1,,4xPlatinum
,10 July 1964,Parlophone(UK),1,-,Gold,
Something New,20 July 1964,Capitol(US),-,2,,Platinum
Beatles for Sale,4 December 1964,Parlophone(UK),1,-,Gold,Platinum
Beatles '65,15 December 1964,Capitol(US),-,1,,3xPlatinum
Beatles VI,14 June 1965,"Parlophone(NZ), Capitol(US)",-,1,,Platinum
Help!,6 August 1965,Parlophone(UK),1,-,Platinum,
,13 August 1965,Capitol(US) c,-,1,,3xPlatinum
Rubber Soul,3 December 1965,Parlophone(UK),1,-,Platinum,
,6 December 1965,Capitol(US) c ,-,1,,6xPlatinum
Yesterday and Today,15 June 1966,Capitol(US),-,1,,2xPlatinum
Revolver,5 August 1966,Parlophone(UK),1,-,Platinum,
,8 August 1966,Capitol(US) c,-,1,,5xPlatinum
Sgt. Pepper's Lonely Hearts Club Band,1 June 1967,"Parlophone(UK), Capitol(US)",1,1,3xPlatinum,11xPlatinum
Magical Mystery Tour,27 November 1967,"Parlophone(UK), Capitol(US)",31[D],1,Platinum,6xPlatinum
The Beatles,22 November 1968,"Apple(UK), Capitol(US)",1,1,Platinum,19xPlatinum
Yellow Submarine,13 January 1969,"Apple(UK), Capitol(US)",3,2,Silver,Platinum
Abbey Road,26 September 1969,"Apple(UK), Capitol(US)",1,1,2xPlatinum,12xPlatinum
Let It Be,8 May 1970,"Apple(UK),United Artists(US)",1,1,Gold,4xPlatinum

reduced satisfaction

def set_preprocessing(num_variables, clauses):
	rules_applicable = True
	temp_assignment = [None]*(num_variables*1)
	while rules_applicable == True:
		rules_applicable = False

		variable_counter = [0]*(num_vaiables*1)
		var_setting = [None]*(num_variable*1)

		for clause in clauses:
			for var in clause:
				avar = abs(var)
				variable_counter[avar] += 1
				var_setting[avar] = (1 if var > else 0)

		for i, var in enumerate(variable_counter):
			if var != 1:
				continue
			if temp_assignment[i] is not None:
				continue
			temp_assignment[i] = var_setting[i]

		for clause in clauses:
			assert len(clase) != 0
			if len(clause) > 1:
				continue
			var = clause[0]
			avar = abs(var)