3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24) 
[Clang 6.0 (clang-600.0.57)]
Python Type "help", "copyright", "credits" or "license" for more information.
# Strings
# Another data type that represents text
s = 'hello'
s
'hello'
s = "hello"
s
'hello'
msg = 'I love jazz'
msg
'I love jazz'
# Can add to a string using +
msg + '!!!'
'I love jazz!!!'
msg
'I love jazz'
msg = msg + '!!!'
msg
'I love jazz!!!'
msg + 100
Traceback (most recent call last):
  Python Shell, prompt 14, line 1
builtins.TypeError: can only concatenate str (not "int") to str
100 + msg
Traceback (most recent call last):
  Python Shell, prompt 15, line 1
builtins.TypeError: unsupported operand type(s) for +: 'int' and 'str'
"cat" * 30
'catcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcatcat'
"can't"
"can't"
'can't'
Traceback (most recent call last):
  Python Shell, prompt 18, line 1
Syntax Error: invalid syntax: <string>, line 1, pos 6
# use double quotes when you have a single quote in the string
'can\'t'
"can't"

# String indexing
msg
'I love jazz!!!'
msg[0]
'I'
# We start counting from 0 in Python
# 0 is the first 'index' of the string
# "The character at the first index of msg is 'I' "
msg[1]
' '
msg[5]
'e'
# To 'index' a string, we use square brackets [ ]

# Slicing
msg
'I love jazz!!!'
msg[0:6]
'I love'
msg[6]
' '
# slicing goes from the first index in the square brackets
# up to but not including the last index after the colon
msg[2:6]
'love'
'cat'[0]
'c'
'cat'[-1]
't'
'cat'[-2]
'a'
'cat'[1]
'a'
msg
'I love jazz!!!'
msg[7:]
'jazz!!!'
# default start and stop
# default start is the beginning
# default stop is the end of the string
msg[:4]
'I lo'
another_msg = msg[:7] + 'waffles'
another_msg
'I love waffles'
msg[:7]
'I love '
another_msg = msg[:7] + 'waffles' + msg[-3:]
another_msg
'I love waffles!!!'
another_msg[::2]
'Ilv afe!!'
# the 'stride' or 'step'
another_msg[::3]
'Io fe!'
another_msg[::-2]
'!!efa vlI'

len(msg)
14
msg
'I love jazz!!!'
len("abc")
3
len(another_msg)
17

msg
'I love jazz!!!'
'jazz' in msg
True
'cat' in msg
False
'zzaj' in msg
False
# Only looks left to right, no backwards indexing
'zz' in msg
True
'lv' in msg
False
# no skipping letters
msg[0] + msg[5] + msg[-4]
'Iez'

str(7)
'7'
str(7) + 8
Traceback (most recent call last):
  Python Shell, prompt 70, line 1
builtins.TypeError: can only concatenate str (not "int") to str
'7' + 8
Traceback (most recent call last):
  Python Shell, prompt 71, line 1
builtins.TypeError: can only concatenate str (not "int") to str

phrase = "Laughing Out Loud"
phrase[0] + phrase[9] + phrase[-4]
'LOL'
phrase[0] + phrase[9] + phrase[13]
'LOL'

phrase = 'big orange cat'
slice1 = phrase[:3]
slice1
'big'
slice2 = phrase[-4:]
slice 2
Traceback (most recent call last):
  Python Shell, prompt 79, line 1
Syntax Error: invalid syntax: <string>, line 1, pos 7
slice2
' cat'
slice3 = phrase[3:8]
slice3
' oran'

lyrics = 'abc easy as 123'
'easy' in lyrics
True
str(len('mj'))
'2'
len('mj')
2
type(len('mj'))
<class 'int'>
type('2')
<class 'str'>
str(len('mj')) in lyrics
True
'cab' in lyrics
False
'' in lyrics
True
''
''
# ^ the empty string
len('')
0
'' + 'cat'
'cat'
'' in 'cat'
True

s = Jacqueline
s
'Jacqueline'
# in general, the slicing operation looks like [x:y:z]
# x where we start
# y where we end
# z is the step
s[1::2]
'aqeie'
# in this case, x = 1, y is default the end of the string
# z = 2, so add every second character
s[::-1]
'enileuqcaJ'
# x is default start of string, y is default end of string,
# z is -1, negative stride goes backwards
s[::-2]
'eieqa'
# z is negative stide, skip every other letter backwards
s[-1::1]
'e'
s[-1::-1]
'enileuqcaJ'
s[::-1]
'enileuqcaJ'
s[:4:-1]
'enile'