print 'False and False =',False and False
print 'False and True  =',False and True
print 'True  and False =',True and False
print 'True  and True  =',True and True

print 'False or False =',False or False
print 'False or True  =',False or True
print 'True  or False =',True or False
print 'True  or True  =',True or True

print 'not False =',not False
print 'not True  =',not True

# nand test:
# see http://en.wikipedia.org/wiki/Logical_NAND
# (A nand B) is not (A and B)

ABList = [(False,False),(False,True),(True,False),(True,True)]
for A,B in ABList:
  print '%s nand %s  ='%(str(A),str(B)),not (A and B)

print True or False

print 1 or 0

print bool(1 or 0)

whatTheySay = True

if whatTheySay:
    print "it's true what they say ..."
else:
    print "it's not true what they say ..."

whatTheySay = 1

if whatTheySay:
    print "it's true what they say ..."
else:
    print "it's not true what they say ..."

3 == (1 * 2**1) + \
     (1 * 2**0)

print bin(3)

print 0b11

101 ==  (1 * 2**6) + \
        (1 * 2**5) + \
        (0 * 2**4) + \
        (0 * 2**3) + \
        (1 * 2**2) + \
        (0 * 2**1) + \
        (1 * 2**0)

print bin(101)

'''
    Explorations in binary!

    We can represent:
   
    binary numbers, e.g.    0b010101
    octal numbers, e.g.     0o755
    hexadecimal, e.g.       0x2A2FF

    but if we print these, 
    by default they are printed as the decimal equivalents.
    
    We can convert to binary, octal or hex string with 
    bin(), oct(), hex()
'''
x = 0b111101101
print bin(x),'is',x,'in decimal'
print bin(x),'is',oct(x),'in octal'
print bin(x),'is',hex(x),'in hexadecimal'

'''
    Bitwise operators: 
'''

A = 521
B = 523
# print as binary:
print A,'\tA:\t',bin(A)
print B,'\tB:\t',bin(B)

# some operations
print '\tA | B:\t',bin(A|B),'\t',A|B
print '\tA ^ B:\t',bin(A^B),'\t\t',A^B
print '\tA & B:\t',bin(A&B),'\t',A&B

'''
    Bitwise shift operators: 
'''

A = 531
print '\tA:\t',bin(A),'\t',A
print '\tA>>1:\t',bin(A>>1),'\t',A>>1
print '\tA>>1:\t',bin(A<<1),'\t',A<<1
print '\tA>>3:\t',bin(A>>3),'\t',A>>3
print '\tA>>3:\t',bin(A<<3),'\t',A<<3

# an example QA value: fill all fields
qa = 0b11111111

print 'qa',qa
print 'binary qa',bin(qa)

# set up masks for the different parameters
mask1 = 0b00000001    # bit 0
mask2 = 0b00000010    # bit 1
mask3 = 0b00000100    # bit 2
mask4 = 0b00011000    # bit 3-4
mask5 = 0b11100000    # bit 5-7

qa1 = qa & mask1
qa2 = qa & mask2
qa3 = qa & mask3
qa4 = qa & mask4
qa5 = qa & mask5

print 'qa1',bin(qa1)
print 'qa2',bin(qa2)
print 'qa3',bin(qa3)
print 'qa4',bin(qa4)
print 'qa5',bin(qa5)


qa1 = (qa & 0b00000001) >> 0    # bit 0
qa2 = (qa & 0b00000010) >> 1    # bit 1
qa3 = (qa & 0b00000100) >> 2    # bit 2
qa4 = (qa & 0b00011000) >> 3    # bit 3-4
qa5 = (qa & 0b11100000) >> 5    # bit 5-7

print 'qa1',bin(qa1)
print 'qa2',bin(qa2)
print 'qa3',bin(qa3)
print 'qa4',bin(qa4)
print 'qa5',bin(qa5)

a = 1
b = 0
print a/b

a = 1
b = 0

''' 
    What do we want to happen if we try to divide by zero?
    In this case, we decide we want to set the result to zero
'''
try:
    print a/b
except ZeroDivisionError:
    print 0

x = 100.
del x

try:
    print x
except NameError:
    print "name 'x' is not defined"

try:
    print '2' + 2     # adding a string to integer doesn't make sense
except:
    print 'you made an error'

import sys

filename = 'files/data/progress.dat'

try:
    f = open(filename)
    s = f.readlines()
    print s[0]
    print s[0]/10
except IOError as e:
    # trap a specific IOError
    print "I/O error reading from %s"%(filename)
except:
    # trap any further errors
    print "Error in processing data from file %s"%filename

# We can use separators other than whitespace with split:
    
data = "1964,1220\n1974,2470\n1984,2706\n1994,4812\n2004,2707"
print "data.split('\\n'):\n\t",data.split('\n')
# note '\\n' in here as '\n' would have printed a newline
# \ is an escape character (as in unix)


# using a generator expressions

fdata1 = (i.split() for i in data.split('\n'))

print list(fdata1)

# two listcomps to split first 
# on \n and then each of these on comma

fdata1 = [i.split() for i in data.split('\n')]

fdata2 = [j[0].split(',') for j in fdata1]

print fdata2

fdata1 = [i.split() for i in data.split('\n')]
fdata2 = [j[0].split(',') for j in fdata1]
fdata = [[int(l) for l in k] for k in fdata2]

print fdata

# or all at once, which works
# but now the meaning of code is too obscure
# so this is poor style

fdata = [[int(l) for l in k] for k in [j[0].split(',') \
            for j in [i.split() for i in data.split('\n')]]]

print fdata

# It might be comprehensible if laid out better

fdata = [[int(l) \
            for l in k] \
                for k in [j[0].split(',') \
                    for j in [i.split() \
                        for i in data.split('\n')]]]

# even so you might find this confusing
# and prefer to do it is smaller chunks

print fdata

print "%20s %s"%('hello','world')
print "%-20s %s"%('hello','world')

pi = 3.1415926536
for format in ["%3.2f","%3.20f","%9.5f","%020.3f"]:
    print format,'\n\t:',format%pi

pi = 3.1415926536
for format in ["%3.2e","%3.20e","%9.5e","%020.3e"]:
    print format,'\n\t:',format%pi

i = 100
for format in ["%i","%3i","%5i","%08i"]:
    print format,'\n\t:',format%i

print "Hey {1}, Hello {0}".format('world','you') 
print '{0}{1}{0}'.format('abra', 'cad') 

# date formatting is a particular example
from datetime import datetime
print """
At the third stroke, it will be 
{:%Y-%m-%d %H:%M:%S}
Beep
Beep
Beep
""".format(datetime.now(),'beep')

# character
print "char: %c %c %c"%(100,101,102)

# octal
print "octal: %o"%(0o755)

# hex
print "hex: %X"%(0xFFF)
print "hex: %x"%(0xFFF)

# example, with directory names

# glob unix style pattern matching for files and directories
import glob

# returns a list (or [] if empty)
# to match the pattern given
file_list = glob.glob("files/data/*.txt")
print "file_list:\n\t",file_list

# e.g. the first string in the list
this_file = file_list[0]

# split the filename on the field '/'
print "\nthis_file.split('/'):\n\t",this_file.split('/')

# so the filename is just the last element in this list
print "\nthis_file.split('/')[-1]:\n\t",this_file.split('/')[-1]

from os import sep # import the string sep from the module os

print "On this system, the file separator is",sep

# example, with directory names

# glob unix style pattern matching for files and directories
import glob
from os import sep 

# returns a list (or [] if empty)
# to match the pattern given
file_list = glob.glob("files{0}data{0}*.txt".format(sep))
print "file_list:\n\t",file_list

# e.g. the first string in the list
this_file = file_list[0]

# split the filename on the field '/' or '\' (sep)
print "\nthis_file.split({0}):\n\t".format(sep),\
                            this_file.split(sep)

# so the filename is just the last element in this list
print "\nthis_file.split({0})[-1]:\n\t".format(sep),\
                            this_file.split(sep)[-1]

import ephem

from ephem import Sun, Observer
from math import pi
from datetime import date,datetime,time

# radians to degrees
rtod = 180./pi

# observer information in pyephem
obs = Observer()

today = date.today()
# or datetime.date(2013, 3, 12)

# put in lat / lon for UCL 
# https://www.google.co.uk/search?q=ucl+longitude+latitude
obs.lat  = '51.5248'
obs.long = '-0.1336'

for hour in xrange(0,24):
    for minute in xrange(0,60,30):
        t = time(hour, minute, 0)
        obs.date = datetime.combine(today, t)
        sun = Sun(obs)
        zenith_elevation = float(sun.alt)*rtod # degrees

        print obs.date,zenith_elevation


from ephem import Sun, Observer
from math import pi
from datetime import date,datetime,time

filename = 'files/data/elevation.dat'
try:
    fp = open(filename,"w")
except:
    print "Failed to open file %s for writing"%filename

# radians to degrees
rtod = 180./pi

# observer information in pyephem
obs = Observer()

today = date.today()
# or datetime.date(2013, 3, 12)

# put in lat / lon for UCL 
# https://www.google.co.uk/search?q=ucl+longitude+latitude
obs.lat  = '51.5248'
obs.long = '-0.1336'

for hour in xrange(0,24):
    for minute in xrange(0,60,30):
        t = time(hour, minute, 0)
        obs.date = datetime.combine(today, t)
        sun = Sun(obs)
        elevation = float(sun.alt)*rtod # degrees
        fp.write("%s %s\n"%(obs.date,elevation))
        
fp.close()
        



# just for interest, let's plot this:

import pylab as plt
%pylab inline

filename = 'files/data/elevation.dat'
fp = open(filename,"r")

hours = []
zeniths = []

for i in fp.readlines():
    data = i.split()
    time = [float(i) for i in data[1].split(':')]
    hour = time[0] + time[1]/60. + time[2]/(60.*60)
    zenith = 90. - float(data[2])
    if zenith <= 90.:
        hours.append(hour)
        zeniths.append(zenith)
fp.close()

# plotting
fig = plt.figure(figsize=(14, 6))
plt.plot(hours,zeniths)
plt.xlabel('hour')
plt.ylabel('solar zenith / degrees')

import urllib2

#as files
url = "http://www.metoffice.gov.uk/hadobs/hadukp/data/monthly/HadSEEP_monthly_qc.txt"

req = urllib2.Request ( url )
raw_data = urllib2.urlopen(req).readlines()

print raw_data[:6]

fp = open('files/data/HadSEEP_monthly_qc.txt','r')
sdata = fp.readlines()
fp.close()

labels = sdata[3].split()
data = [i.split() for i in sdata[4:]]
j = 0
rdata = [[float(data[i][j]) \
         for i in xrange(len(data))]\
         for j in xrange(len(data[0]))]

print rdata[0]

# set up a 
dataset = {}
for i,k in enumerate(labels):
    dataset[k] = rdata[i]

print dataset['YEAR']

dataset = dict(zip(labels,rdata))

print dataset['YEAR']

import pylab as plt
%pylab inline
for i,JFM in enumerate([['JAN','FEB','MAR'],['APR','MAY','JUN'],\
              ['JUL','AUG','SEP'],['OCT','NOV','DEC']]):
    plt.figure(i,figsize=(14, 6))
    plt.xlabel('Year')
    plt.ylabel('Precip. (mm)')
    for month in JFM:
        plt.ylim(0,250)
        plt.xlim(dataset['YEAR'][0],dataset['YEAR'][-1])
        plt.title(str(JFM))
        plt.plot(dataset['YEAR'],dataset[month])

plt.figure(i+1,figsize=(14, 6))
plt.xlabel('Year')
plt.ylabel('Precip. (mm)')
plt.title('ANN')
plt.ylim(0,1100)
plt.xlim(dataset['YEAR'][0],dataset['YEAR'][-1])
plt.plot(dataset['YEAR'],dataset['ANN'])

# Read files/data/heathrowdata.txt as above into data as float
# doing some clever things to deal with file markers
# i.e. where it says #  Provisional or # we will not worry about
# that for the moment
# where it has fillers, ---, replace by -999

fp = open('files/data/heathrowdata.txt','r')
ldata = [i.replace('---','-999').replace('#  Provisional','').replace('#','').split() \
                     for i in fp.readlines()[7:]]
data = [[float(k) for k in j] for j in ldata]
fp.close()

# The reading by line is a bit inconvenient, so rotate the 
# dataset
rdata = [[data[j][i] for j in xrange(len(data))] for i in xrange(len(data[0]))]

# set some labels for each column
labels = ['year','month','tmax (degC)','tmin (degC)',\
          'air frost (days)','rain (mm)','sun (hours)'] 

# generate a dictionary with the labels as keys
items = dict(zip(labels,rdata))

import pylab as plt
# its quite difficult to add arrays
# so we have to loop over each item
time = [items['year'][i] + items['month'][i]/12. for i in xrange(len(items['year']))]

for i,label in enumerate(labels[2:]):
    plt.figure(i,figsize=(14, 6))
    plt.xlabel('year')
    plt.ylabel(label)
    # filter out the -999 values
    x = [time[j] for j,i in enumerate(items[label]) if i != -999]
    y = [i for i in items[label] if i != -999]
    plt.plot(x,y)

data = "1964 1220 1974 2470 1984 2706 1994 4812 2004 2707"
sdata = data.split()

for i in xrange(0,len(sdata),2):
    print ' '.join(sdata[i:i+2])

fdata = [int(s) for s in data.split()]

print fdata

data = "1964 1220 1974 2470 1984 2706 1994 4812 2004 2707"

fdata = []
for s in data.split():
    fdata.append(int(s))
        
print fdata

data = "1964 1220 1974 2470 1984 2706 1994 4812 2004 2707"
fdata = [int(s) for s in data.split()]

# use slicing to separate the odd
# and even data
years     = fdata[0::2]
emissions = fdata[1::2]

print years
print emissions

fdata = (int(s) for s in data.split())
print 'fdata is',fdata

for i in fdata:
    print i