Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24) 
[Clang 6.0 (clang-600.0.57)] on darwin
Type "copyright", "credits" or "license()" for more information.
>>>  n
SyntaxError: unexpected indent
>>> s = "I need a latte badly"
>>> len(s)
20
>>> s[0]
'I'
>>> s[19]
'y'
>>> s[-1]
'y'
>>> s[1:5]
' nee'
>>> s[3:4]
'e'
>>> s[4:5]
'e'
>>> s[5:6]
'd'
>>> s[5:5]
''
>>> t = ""
>>> u = " "
>>> s[:4]
'I ne'
>>> s[4:]
'ed a latte badly'
>>> s[:]
'I need a latte badly'
>>> s[2:6]
'need'
>>> s[9:15]
'latte '
>>> s[9:14]
'latte'
>>> s[2:6] + s[9:14]
'needlatte'
>>> s[2:6] + " " + s[9:14]
'need latte'
>>> s[2:6]
'need'
>>> 5*s[2:6]
'needneedneedneedneed'
>>> t = s[2:6]
>>> t
'need'
>>> t.upper()
'NEED'
>>> u = t.upper()
>>> u
'NEED'
>>> v = u.lower()
>>> v
'need'
>>> s
'I need a latte badly'
>>> s.count("e")
3
>>> s.count("a")
3
>>> s.count("i")
0
>>> len("abcdefghijklmnopqrstuvwxyz")
26
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> letter2index("a")
0
>>> letter2index("b")
1
>>> letter2index("w")
22
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> index2letter(22)
'w'
>>> index2letter(4)
'e'
>>> 29 % 26
3
>>> 456 % 26
14
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> caesar("attack at down")
Traceback (most recent call last):
  File "<pyshell#42>", line 1, in <module>
    caesar("attack at down")
  File "/Users/koc/Desktop/enc.py", line 17, in caesar
    encm = (m + 3) % 26
TypeError: unsupported operand type(s) for +: 'NoneType' and 'int'
>>> letter2index("b")
1
>>> index2letter(4)
'e'
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> caesar("attack at down")
Traceback (most recent call last):
  File "<pyshell#45>", line 1, in <module>
    caesar("attack at down")
  File "/Users/koc/Desktop/enc.py", line 17, in caesar
    encm = (m + 3) % 26
TypeError: unsupported operand type(s) for +: 'NoneType' and 'int'
>>> u = "attack at down"
>>> u
'attack at down'
>>> caesar(u)
Traceback (most recent call last):
  File "<pyshell#48>", line 1, in <module>
    caesar(u)
  File "/Users/koc/Desktop/enc.py", line 17, in caesar
    encm = (m + 3) % 26
TypeError: unsupported operand type(s) for +: 'NoneType' and 'int'
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> u = "attack at down"
>>> caesar(u)
a
0
3
d
d
t
19
22
w
dw
t
19
22
w
dww
a
0
3
d
dwwd
c
2
5
f
dwwdf
k
10
13
n
dwwdfn
 
None
Traceback (most recent call last):
  File "<pyshell#50>", line 1, in <module>
    caesar(u)
  File "/Users/koc/Desktop/enc.py", line 19, in caesar
    encm = (m + 3) % 26
TypeError: unsupported operand type(s) for +: 'NoneType' and 'int'
>>> 
>>> u
'attack at down'
>>> u = "attackatdown"
>>> caesar(u)
a
0
3
d
d
t
19
22
w
dw
t
19
22
w
dww
a
0
3
d
dwwd
c
2
5
f
dwwdf
k
10
13
n
dwwdfn
a
0
3
d
dwwdfnd
t
19
22
w
dwwdfndw
d
3
6
g
dwwdfndwg
o
14
17
r
dwwdfndwgr
w
22
25
z
dwwdfndwgrz
n
13
16
q
dwwdfndwgrzq
'dwwdfndwgrzq'
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> u = "attackatdown"
>>> caesar(u)
'dwwdfndwgrzq'
>>> u = "attackatdawn"
>>> caesar(u)
'dwwdfndwgdzq'
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> u = "attackatdawn"
>>> caesar(u, 3)
'dwwdfndwgdzq'
>>> caesar(u, 4)
'exxegoexhear'
>>> caesar(u, 3)
'dwwdfndwgdzq'
>>> caesar('dwwdfndwgdzq', -3)
'attackatdawn'
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> caesar("attack at dawn", 5)
Traceback (most recent call last):
  File "<pyshell#64>", line 1, in <module>
    caesar("attack at dawn", 5)
  File "/Users/koc/Desktop/enc.py", line 17, in caesar
    encm = (m + key) % 26
TypeError: unsupported operand type(s) for +: 'NoneType' and 'int'
>>> 
=========== RESTART: /Users/koc/Desktop/enc.py ===========
>>> caesar("attack at dawn", 7)
'haahjr ha khdu'
>>> caesar("haahjr ha khdu", -7)
'attack at dawn'
>>> encm = (m + key) % 26
Traceback (most recent call last):
  File "<pyshell#67>", line 1, in <module>
    encm = (m + key) % 26

NameError: name 'm' is not defined

>>> 
>>> 
>>> 
>>>