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MAC:Thu Feb 10:10:21:~> python
Python 3.10.0 (v3.10.0:b494f5935c, Oct  4 2021, 14:59:19) [Clang 12.0.5 (clang-1205.0.22.11)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> # < > <= >= != ==   relational operators
>>> # is
>>> # is checks for equality of identity
>>> x = 5
>>> y = 5
>>> x == y
True
>>> x is y
True
>>> x = 5000
>>> y = 5000
>>> x == y
True
>>> x is y
False
>>> x = "cow"
>>> y = "cow"
>>> x == y
True
>>> x is y
True
>>> x = 3 
>>> x += 5
>>> x *= 1 + 2
>>> x
24
>>> ##  x op=y  same as x = x op (y)
>>> a = "abc"
>>> id(a)
4312163376
>>> a += "def"
>>> id(a)
4313114224
>>> count = 0
>>> count += 1
>>> count
1
>>> count += 1
>>> count
2
>>> count += 1
>>> count
3
>>> levels = [214.6, 214.7, 217.0, 218.5, 218.5, 218.4, 218.3, 218.1,# 
... 217.9, 217.8, 217.5, 217.2, 217.2, 216.9, 216.8, 216.7, 216.7,#
... 216.9, 217.2, 217.3, 217.3, 217.1, 217.0, 216.7, 216.5, 216.3,#
... 216.2, 216.2, 216.3, 216.3, 216.3]
>>> levels
[214.6, 214.7, 217.0, 218.5, 218.5, 218.4, 218.3, 218.1, 217.9, 217.8, 217.5, 217.2, 217.2, 216.9, 216.8, 216.7, 216.7, 216.9, 217.2, 217.3, 217.3, 217.1, 217.0, 216.7, 216.5, 216.3, 216.2, 216.2, 216.3, 216.3, 216.3]
>>> levels[0]
214.6
>>> levels[1]
214.7
>>> s = "abcdef"
>>> s[0]
'a'
>>> s[1]
'b'
>>> len(s)
6
>>> len(levels)
31
>>> 214.6 in levels
True
>>> # in checks for membership of a object in a list using ==
>>> "a" in s
True
>>> "ac" in s
False
>>> #  ac is not a substring of s.
>>> [216.3, 216.3] in levels
False
>>> # no sublist checking
>>> crazy = [1,2,3,[1,2,3]]
>>> crazy
[1, 2, 3, [1, 2, 3]]
>>> len(crazy)
4
>>> crazy[3]
[1, 2, 3]
>>> crazy[3][1]
2
>>> ## numerical list functions
>>> sum(levels)
6726.400000000001
>>> sum(levels)/len(levels)
216.98064516129034
>>> max(levels)
218.5
>>> min(levels)
214.6
>>> levels[5:10]
[218.4, 218.3, 218.1, 217.9, 217.8]
>>> ## lists are MUTABLE
>>> 
>>> x = [1,2,3,4,5]
>>> x
[1, 2, 3, 4, 5]
>>> x[0] = 10
>>> x
[10, 2, 3, 4, 5]
>>> # entries in a list are lvalues (left-hand assignment)
>>> y = x
>>> y
[10, 2, 3, 4, 5]
>>> x
[10, 2, 3, 4, 5]
>>> x[3] = -1
>>> x
[10, 2, 3, -1, 5]
>>> y
[10, 2, 3, -1, 5]
>>> #  Rosemary Woods:  Richard Nixon's secretary
>>> x
[10, 2, 3, -1, 5]
>>> x[2:4] = []
>>> x
[10, 2, 5]
>>> x[2:3] = [10, 20, 30, 40, 50]
>>> x
[10, 2, 10, 20, 30, 40, 50]
>>> #I can splice and slice
>>> 
>>> type(x)
<class 'list'>
>>> t = (1,2,3,4,5)
>>> type(t)
<class 'tuple'>
>>> t[0]
1
>>> t[3:]
(4, 5)
>>> t
(1, 2, 3, 4, 5)
>>> t[0] = 10
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment
>>> x = [1,2,3,4]
>>> t = (1,2,3,4)
>>> id(x)
4313812416
>>> x += [5,6,7]
>>> id(x)
4313812416
>>> id(t)
4313036368
>>> t += (5,6,7)
>>> t
(1, 2, 3, 4, 5, 6, 7)
>>> id(t)
4312346400
>>> #relatonal operators????
>>> 
>>> eclectic = [1, "cow", 4.5, True, ["a", "b", "c"]]
>>> #  list is a heterogeneous sequence type
>>> #  list is mutable
>>> #  tuple is a heterogeneous immutable sequence type
>>> 
>>> ## strings and relationals
>>> "abc" < "abd"
True
>>> "XYZ" < "abc"
True
>>> "123" < "11"
False
>>> "52" < "10001"
False
>>> "Cowabunga" < "aardvark"
True
>>> "1" < "a"
True
>>> ";" < ":"
False
>>> ##  upper case < lower case
>>> ##  digits < lower case
>>> ord("a")
97
>>> ord(";")
59
>>> ord("A")
65
>>> "Aardvark" < "Aardwolf
  File "<stdin>", line 1
    "Aardvark" < "Aardwolf
                 ^
SyntaxError: unterminated string literal (detected at line 1)
>>> "Aardvark" < "Aardwolf"
True
>>> "Aardvark" < "AardWolf"
False
>>> bin("a")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object cannot be interpreted as an integer
>>> bin(ord("a"))
'0b1100001'
>>> bin(ord("A"))
'0b1000001'
>>> ^D
MAC:Thu Feb 10:11:22:~> vi sampler.txt
MAC:Thu Feb 10:11:23:~> xxd -b sampler.txt bin.txt
MAC:Thu Feb 10:11:23:~> vi bin.txt
MAC:Thu Feb 10:11:27:~> python
Python 3.10.0 (v3.10.0:b494f5935c, Oct  4 2021, 14:59:19) [Clang 12.0.5 (clang-1205.0.22.11)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> x = "Abacus"
>>> y = "bubblehead"
>>> x < y
True
>>> x = "abacus"
>>> y = "Bubblehead"
>>> x < y
False
>>> x.upper() < y.upper()
True
>>> x.lower() < y.lower()
True
>>> "52" > "10001"
True
>>> "type determines context"
'type determines context'
>>> bool([])
False
>>> bool([3,2,2])
True
>>> ##  truthiness:  an object is truthy if casts as a boolean to True
>>> ##  falsiness: falsy if it cast as a boolean to false
>>> 
>>> bool(0)
False
>>> bool(0.0)
False
>>> bool("")
False
>>> bool([])
False
>>> bool((,))
  File "<stdin>", line 1
    bool((,))
          ^
SyntaxError: invalid syntax
>>> bool((4,))
True
>>> x = (4,)
>>> x
(4,)
>>> x = [3,1,6,8,4]
>>> sorted(x)
[1, 3, 4, 6, 8]
>>> x
[3, 1, 6, 8, 4]
>>> x = ["a", True, 5]
>>> sorted(x)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: '<' not supported between instances of 'bool' and 'str'
>>> x = [3, 1.4, 9, 6.02e23, 1e-6]
>>> x
[3, 1.4, 9, 6.02e+23, 1e-06]
>>> sorted(x)
[1e-06, 1.4, 3, 9, 6.02e+23]
>>> x.sort(0
... )
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: sort() takes no positional arguments
>>> x.sort()
>>> x
[1e-06, 1.4, 3, 9, 6.02e+23]
>>>