(base) MAC:Thu Feb 04:10:24:students> python
Python 3.8.5 (default, Sep  4 2020, 02:22:02) 
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 
(base) MAC:Thu Feb 04:10:25:students> !p
python
Python 3.8.5 (default, Sep  4 2020, 02:22:02) 
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 5 + 6
11
>>> type(5)
<class 'int'>
>>> 5*6
30
>>> 5**6
15625
>>> 5/6
0.8333333333333334
>>> type(5/6)
<class 'float'>
>>> 5//6
0
>>> 5-6
-1
>>> # infix binary operators
>>> #how many cubic feet are in a cubic mile?
>>> 5280**3
147197952000
>>> 365%7
1
>>> 366%7
2
>>> 368%7
4
>>> 7*52
364
>>> 5-6
-1
>>> 5^7
2
>>> 2**1000
10715086071862673209484250490600018105614048117055336074437503883703510511249361224931983788156958581275946729175531468251871452856923140435984577574698574803934567774824230985421074605062371141877954182153046474983581941267398767559165543946077062914571196477686542167660429831652624386837205668069376
>>> ## IEEE754 standard
>>> ## this is a 64-bit floating point number
>>> 2**64
18446744073709551616
>>> 2/3
0.6666666666666666
>>> .1 + .1 + .1
0.30000000000000004
>>> 1/4
0.25
>>> .1 + .1 +.1 == .3
False
>>> 2.5 + 3.5
6.0
>>> 2.5 - 3.5
-1.0
>>> 2.5 * 3.5
8.75
>>> 2.5 / 3.5
0.7142857142857143
>>> 4**(.5)
2.0
>>> 4**(1/3)
1.5874010519681994
>>> 5 % 2.5
0.0
>>> 5.3 % 2.5
0.2999999999999998
>>>  7 + 6.5
  File "<stdin>", line 1
    7 + 6.5
    ^
IndentationError: unexpected indent
>>> 7 + 6.5
13.5
>>> float(5)
5.0
>>> int(4.5)
4
>>> #  cast is a temporary request to regard a datum as being of another type.
>>> int(-4.5)
-4
>>> ##truncates toward zero
>>> z = complex(3,4)
>>> z
(3+4j)
>>> z*z
(-7+24j)
>>> #order of ops is no surprise among arithmetic operators
>>> 4 + 7*3
25
>>> 3*4/2*8
48.0
>>> # * and / have equal precedence and associate from left to right.
>>> 
>>> 3-4+5-10
-6
>>> #associate from left to right.
>>> 2**4**2
65536
>>> ## ** associates from right to left
>>> 
>>> abs(-5)
5
>>> abs(-6.5)
6.5
>>> #Python has built-in functions that to lots of useful stuff.
>>> ##Relational operators
>>>  4 > 5
  File "<stdin>", line 1
    4 > 5
    ^
IndentationError: unexpected indent
>>> 4 > 5
False
>>> 5*6 < 2*4
False
>>> ##relational have lower precedence than any arithmetic operator.
>>> -5
-5
>>> -complex(3,4)
(-3-4j)
>>> -5.6
-5.6
>>> 5*6 >= 2*4
True
>>> 5*6 <= 2*4
False
>>> 5*6 == 30
True
>>> #  == is isequalto
>>> .3 == .1 + .1 + .1
False
>>> #  do not compare floats for equality.
>>> 5 != 6
True
>>> type(False)
<class 'bool'>
>>> print("Hello")
Hello
>>> quit()
(base) MAC:Thu Feb 04:11:05:students> pwd
/Users/morrison/20202021/S2/4240/students
(base) MAC:Thu Feb 04:11:06:students> cd ../ch2/
(base) MAC:Thu Feb 04:11:08:ch2> ls
hello.py
(base) MAC:Thu Feb 04:11:08:ch2> python hello.py
(base) MAC:Thu Feb 04:11:09:ch2> python hello.py
Hello, World!
(base) MAC:Thu Feb 04:11:09:ch2> python hello.py
Hello, World!
15
(base) MAC:Thu Feb 04:11:10:ch2> python hello.py
Hello, World!
15
15 cows False
15  **  cows  **  False
No new line. please!
a
b	c	d
e
(base) MAC:Thu Feb 04:11:21:ch2> python format.py
  File "format.py", line 8
    of this game"""")
                    ^
SyntaxError: EOL while scanning string literal
(base) MAC:Thu Feb 04:11:36:ch2> python format.py
cat is chasing a dog
5  3 4  3
5*3 = 15
5*3 = 15
C:\Windoze\sux\bill\gates
Here are the rules
of this game
(base) MAC:Thu Feb 04:11:37:ch2> python
Python 3.8.5 (default, Sep  4 2020, 02:22:02) 
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> #string: a glob of text
>>> type("hello")
<class 'str'>
>>> "some" + "thing"
'something'
>>> "*"*50
'**************************************************'
>>> print("5*3 = " + "15")
5*3 = 15
>>> "*"*(-4)
''
>>> ##string literals can be bouned by single or double quotes
>>> 
>>> 'sone' + 'thing'
'sonething'
>>> 'some' + "thing"
'something'
>>> 'double quotes like these " are not special when single quotes are used'
'double quotes like these " are not special when single quotes are used'
>>> x = "abcdefghijklmnopqrstuvwxyz"
>>> s
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 's' is not defined
>>> x
'abcdefghijklmnopqrstuvwxyz'
>>> len(x)
26
>>> x[1]
'b'
>>> x[0]
'a'
>>> x[2]
'c'
>>> x[:2]
'ab'
>>> x[2:]
'cdefghijklmnopqrstuvwxyz'
>>> x[:2] + x[2:]
'abcdefghijklmnopqrstuvwxyz'
>>> x[3:6]
'def'
>>> x[50]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: string index out of range
>>> x[::2]
'acegikmoqsuwy'
>>> x[1::2]
'bdfhjlnprtvxz'
>>> x[1:7:2]
'bdf'
>>> #start, stop, skip
>>>