# Contents
# 1. in : some more comments
# 2. for loops; implementing for loops using while
# 3. for loops: playing with list indices
# 4. Changing the list in the for loop
# 5. enumerate
# 7. string formatting : pg 12

# Don't worry about the following two functions right now:
head_count = 0

def header(hstr) :
	global head_count
	head_count += 1
	ln = ""
	for i in range(75) :
		ln += '-'
	print ln
	print "%02d.\t%s" % (head_count, hstr)
	print ln
	print " "

def pause() :
	raw_input("To continue, press enter ... ")

# 1. in : some more comments
header("The builtin command : in")
my_lst = [5, 7, 9]
print "4 in my_lst :", (4 in my_lst)
print "7 in my_lst :", (7 in my_lst)
print "a in  \"bad\" :", ('a' in "bad")
print "o in  \"bad\" :", ('o' in "bad")
print " o   in   o :", ('o' in 'o')
print " a   in   o :", ('a' in 'o')
# Check what error this gives : 
# print "4 in 4 : ", (4 in 4)
print " 4   in [4] :", (4 in [4])

pause()

# 2. for loops; implementing for loops using while
header("for loops: glorified while loops")

somelist = ["Entry 1", "Entry 2", "Entry 3", "Entry 4", "Entry 5", "Entry 6"]
for item in somelist :
	print "Processing \"" + item + "\"."

print
print """This can be implemented as a while loop as follows : """

i = 0
while i < len(somelist) :
	print "Processing \"" + somelist[i] + "\"."
	i += 1

pause()

# 3. for loops: playing with list indices
header("range, what for?")
print "range(10) : ",  range(10) # This we know.
print "range(-10, 10) : ",  range(-10, 10)
print "range(-10, 10, 2) : ",  range(-10, 10, 2)

print "To print fractions we need a for loop"
pt5increments = []
for i in range(20) :
	pt5increments.append(0.5 * i)

print pt5increments
print
pause()

# Suppose you want increments by 1.5 for some reason. You can also do that
print "For general increments : eg incr = 1.5 : "
gen_incr = []
incr = 1.5 # in this code we are assuming increment has at most 2 dec places
start = 2
end = 13
# we do the following so that end gets included in the list
if round((float(end) - start)/incr) == (float(end) - start)/incr :
	end = end + incr
new_start = 100 * start
new_end = 100 * end
new_incr = int(100 * incr)
for i in range(new_start, new_end, new_incr) :
	gen_incr.append(1.0 * i / 100)

print gen_incr
print

pause()

# A short CtoF function
# Suppose you want to convert temp from 25 - 40 C to F with jumps of 2.5 C
incr = 2.5 # you can use input if you want
start = 25
end = 40

# as usual, fix the issue at the "end"
if round((float(end) - start)/incr) == (float(end) - start)/incr :
	end += incr

# Now, make a list as before
for temph in range((100 * start), int(100 * end), int(100 * incr)) :
	C_temp = float(temph)/100
	F_temp = 9.0 / 5 * C_temp + 32
	print "%010.3f C = %010.3f F" % (C_temp, F_temp)

pause()
print
# 4. Changing the list in the for loop
# Suppose you want to print a log table for integers from 1 to n
header("Changing the list in the for loop; enumerate")

import math
log_of_nos_to_10 = range(1, 11)
print log_of_nos_to_10
for no in log_of_nos_to_10 :
	no = math.log(no)
print log_of_nos_to_10
pause()
print
print "enumerate : ", enumerate(log_of_nos_to_10)
print """However "in" works when used as follows.
	   ((0, 1) in enumerate(log_of_nos_to_10)) : """, ((0, 1) in \
		   enumerate(log_of_nos_to_10)), """
	   ((2, 2) in enumerate(log_of_nos_to_10)) : """, ((2, 2) in \
		   enumerate(log_of_nos_to_10))
pause()
print

for (i, no) in enumerate(log_of_nos_to_10) :
	log_of_nos_to_10[i] = (math.log(no), math.log10(no))
print log_of_nos_to_10