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

print()

# built-in function len() returns the length of its string parameter
# \ used to specify a special character: \t is tab, \n is new line,
# \' is single quote, \" is double quote, \\ is backslash

a = 'abcd'
b = 'a b c d'
c = 'a	b'
d = 'a\tb'
e = 'it\'s'
f = 'a\nb'

print( '##### string length and \\' )

na = len( a )
nb = len( b )
nc = len( c )
nd = len( d )
ne = len( e )
nf = len( f )

### pause to think what has happened

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

print( 'len(', a, ') =', na )
print( 'len(', b, ') =', nb )
print( 'len(', c, ') =', nc )
print( 'len(', d, ') =', nd )
print( 'len(', e, ') =', ne )
print( 'len(', f, ') =', nf )

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

# operator + when given two string operands does concatenation

print( '##### concatenation' )

a = 'abc'
b = 'def'
c = a + b

print( a, '+', b, '=', c )

### pause to think what has happened

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

# operator + when given a string and non-string operands throws up

#water = 'H' + 2 + '0'

#print( water )

# built-in function str() returns a text representatiom of its
# parameter

print( '##### str() converts objects to a string representation' )

water = 'H' + str( 2 ) + 'O'

print( "'H' + str( 2 ) + 'O' =", water )

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

# operator * when given a left operator string s and a right integer
# integer operand n produces a string that is a repeated concatenation
# of s, n times

print( '##### * operator produces repeated concatenation' )
t  = 'Wahoo-Wah!' * 3 

print( "'Wahoo-Wah!' * 3 =", t )

### pause to think what has happened

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

# operator [] is the string index operator -- it provides access to
# a string subsequence. depending upon its operands it is all called
# subscripting and slicing

print( '##### [] is the string index operator' )
s = 'abcdefghij'
print( 's =', s )
print( '    0123456789' )

### pause to think what has happened

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

print( '##### if the [] operand brackets an int, it is subscripting' )
x = s[ 0 ]
y = s[ 4 ]
z = s[ 9 ]

print( 's[ 0 ] = ', x )
print( 's[ 4 ] = ', y )
print( 's[ 9 ] = ', z )

### pause to think what has happened

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

print( '##### if the [] operand brackets a : expession, it is slicing' )
s1 = s[ 1 : 4 ]
s2 = s[   : 4 ]
s3 = s[ 1 :   ]
s4 = s[   :   ]

print( 's[ 1 : 4 ]  = ', s1 )
print( 's[   : 4 ]  = ', s2 )
print( 's[ 1 :   ]  = ', s3 )
print( 's[   :   ]  = ', s4 )

### pause to think what has happened

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

# bonus -- stripping and splitting

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

print( '##### stripping' )

q = '   Look there is a   Blibbering Humdinger  '

q.strip()                   # q is uneffected. strip() produces
                            # a new string

print( "q = '" + q + "'"  )

### pause to think what has happened

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

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

print( "q = '" + q + "'"  )
print( "s = '" + s + "'" )

### pause to think what has happened

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

# strings can produce their component words.  The ability
# come from a string's  method split()
#                        ------

print( '##### splitting' )

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

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

### pause to think what has happened

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

school, subject, number = c.split()   # splits person into list of indiviudal
                                      # words, which for this example is a
                                      # name, home planet, and age

print( fruit, 'costs', price, 'per pound' )
print( 'School:', school, '  subject:', subject,
            '  number:', number )

### pause to think what has happened

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

s1 = f.split()              # s1 is a 2-element list
s2 = c.split()              # s2 is a 3-element list

print( 's1 = ', s1 )
print( 's2 = ', s2 )

print()