''' Purpose: continue string manipulation introduction
'''

print()

# strings can produced strip versions of themselves -- a
# version without LEADING or TRAILING whitespace.  Internal
# whitespace is uneffected.  The ability comes from the string
# member method strip()
# ------------

q = '   There is a door open    to walk through '

print( 'q: \'' + q + '\''  )

print(); input( 'Enter when ready: ' ); print()

print( '### mis-attempted stripping' )

# New function! .strip() is a function for strings!
q.strip()                   # q is uneffected. strip() always produces
                            # a new string

# q.strip() applies the strip() function to string q
# The strip() function hands back a new string that has no leading and trailing whitespace.

print( 'q.strip():' , q.strip() )

print( 'q: \'' + q + '\''  )

# q did not change! q.strip() does not change q!!
# The function hands back a NEW string with no leading and trailing whitespace.

# When you call strip() on a string, it does not change the original string.
# Strings are IMMUTABLE (they cannot be changed!) - we can call functions on strings and they
# hand back NEW strings that are ALTERED versions of the original string (like a copy!)
# We usually do variable = q.strip() or something like that (store the stripped version in a variable)

print(); input( 'Enter when ready: ' ); print()

print( '### stripping' )

s = q.strip()               # q is still uneffected, but s is a
                            # stripped version of s

print( 's = q.strip()' )
print( 'q: \'' + q + '\''  ) # q is unchanged
print( 's: \'' + s + '\'' ) # s is a copy of q which the function applied to q (no leading / trailing whitespace)

# Leading and Trailing Whitespace: Whitespace at the beginning / end of a string (doesn't get rid of space
# in the middle / in between words in a string if we just call strip() with no arguments)

# strip() by default removes leading/trailing whitespace
# It CAN take in an optional argument in the parentheses to strip (get rid of) what you want to get
# rid of in the string.

# The original string is unchanged!
# The stripped version is stored in another variable!

print(); input( 'Enter when ready: ' ); print()

# strings can produce their component words.  The ability comes
# from the string member method split()
#                 -------------

print( '### splitting' )

f = 'bananas  $0.69'
c = 'SEAS CS 1112'

print( 'f: \'' + f + '\'' )
print( 'c: \'' + c + '\'' )

print(); input( 'Enter when ready: ' ); print()

fruit, price = f.split()              # splits fruit into list of individual
                                      # words, which for this example is a
                                      # fruit and its cost

print( 'fruit, price = f.split()' )
print( fruit, 'costs', price, 'per pound' )

print(); input( 'Enter when ready: ' ); print()


school, subject, number = c.split()   # splits coutse listing  into list of
                                      # individual words, which for this
                                      # example is a school, subject, and
                                      # course number

# split() is another string function we touched on last class! It returns a list of words split
# based on whitespace in the original string.

print( 'school, subject, number = c.split()' )
print( 'School:', school, '  subject:', subject, '  number:', number )

### pause to think what has happened

print(); input( 'Enter when ready: ' ); print()

print( '### list making' )

list1 = f.split()              # list1 is a 2-element list
list2 = c.split()              # list2 is a 3-element list

print( 'list1 = f.split()' )
print( 'list2 = c.split()' )

print( 'list1: ', list1 )
print( 'list2: ', list2 )

# Assigning Variables to .split():
# list1 = f.split() -> STORES THE LIST OF WORDS / SPLIT STRINGS IN THE VARIABLE
# fruit, price = f.split() -> ASSIGNS THE FIRST ITEM IN THE LIST TO FRUIT AND THE SECOND ITEM IN THE LIST

# f is 'bananas $0.69'
# f.split -> ['banana', '$0.69']
# A list in Python is denoted using brackets with items separated with commas [...,...,...]
# More on lists later!