The document discusses why Python is a popular programming language. It notes that Python has an easy to learn syntax, built-in datatypes like lists and strings, runs on many machine types, has many scientific libraries, a large community of scientists using it, and is the #1 programming language in universities. It also allows experimentation via a shell mode.

5. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific libraries (SciPy, NumPy)
•Large community of scientists using it
•#1 programming language in universities
•Shell mode for experimentation

6. Why Python?
•Easy to learn syntax

7. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.

8. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines

9. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific libraries (SciPy, NumPy)

10. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific libraries (SciPy, NumPy)
•Large community of scientists using it

11. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific libraries (SciPy, NumPy)
•Large community of scientists using it
•#1 programming language in universities

12. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific libraries (SciPy, NumPy)
•Large community of scientists using it
•#1 programming language in universities
•Shell mode for experimentation

16. Assignment uses =
First assignment makes the var
(not ‘dim’ needed)

17. Comparison uses ==

18. Comparison uses ==
“Print” prints all datatypes (no toString() needed)

19. Logical operators are words

21. Multi assign

22. Multi assign

23. Datatypes

24. Why?

25. Why?
Integers are the default

28. “” and ‘’ are both okay

29. Whitespace

32. This whitespace has meaning!

34. Indentation marks a block
No begin/end or {}

35. Comments start with #

36. Understanding Assignment

37. What exactly happens is:

38. What exactly happens is:
Type: Integer
Data: 5
memory

39. What exactly happens is:
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory

40. What exactly happens is:
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory

41. What exactly happens is:
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory

42. Important:
Python determines the type automatically
Decides when to delete too (garbage collection)
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory

43. Important:
Python determines the type automatically
Decides when to delete too (garbage collection)
Basic data types (int, float, string) are immutable
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory

45. What exactly happens is:
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory

46. What exactly happens is:
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory
Type: Integer
Data: 6

47. What exactly happens is:
Type: Integer
Data: 5
Name: a
Ref: <address1>
name list
memory
Type: Integer
Data: 6

48. What exactly happens is:
Name: a
Ref: <address1>
name list
memory
Type: Integer
Data: 6

49. What exactly happens is:
This is the garbage collector at work
Name: a
Ref: <address1>
name list
memory
Type: Integer
Data: 6

50. Another example

51. Another example
Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory

52. Another example
Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory
Name: x
Ref: <address1>

53. Another example
Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory
Type: Integer
Data: 10
Name: x
Ref: <address2>

56. Lists may contain a mix

57. Lists may contain a mix
Can even contain other lists

58. Looking up items
Counting starts at 0

59. Looking up items
Counting starts at 0
We can also count from the end!

60. Looking up items
Counting starts at 0
We can also count from the end!
‘index out of range’ is a common error

61. Slicing

62. Slicing

63. Slicing

64. Slicing
Both arguments are optional

65. Slicing
Both arguments are optional

66. Slicing
Both arguments are optional

67. Slicing
Both arguments are optional
Starting at the end also allowed

69. Lists are mutable!

70. Remember this example?

71. Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory
Remember this example?

72. Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory
Name: x
Ref: <address1>
Remember this example?

73. Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory
Type: Integer
Data: 10
Name: x
Ref: <address2>
Remember this example?

74. How will this work?
Type: List
Data: [1,2,3]
Name: list
Ref: <address1>
name list
memory

75. How will this work?
Type: List
Data: [1,2,3]
Name: list
Ref: <address1>
name list
memory
Name: list2
Ref: <address1>

76. Type: Integer
Data: 6
Name: a
Ref: <address1>
name list
memory
Name: x
Ref: <address1>
So far everything is as expected

77. How will this work?
Type: List
Data: [1,2,3]
Name: list
Ref: <address1>
name list
memory
Name: list2
Ref: <address1>

78. How will this work?
Type: List
Data: [3,2,1]
Name: list
Ref: <address1>
name list
memory
Name: list2
Ref: <address1>

79. How will this work?
Type: List
Data: [3,2,1]
Name: list
Ref: <address1>
name list
memory
Name: list2
Ref: <address1>

80. How will this work?
Type: List
Data: [3,2,1]
Name: list
Ref: <address1>
name list
memory
Name: list2
Ref: <address1>

81. To avoid this, use [:] to copy

82. To avoid this, use [:] to copy

83. To avoid this, use [:] to copy

86. Popquiz!!
What does this do?

87. Popquiz!!
What does this do?

91. Variables are case sensitive!

92. Some names are reserved

93. Some names are reserved

94. Some names are reserved

96. Remember this did not
multiply list items?

97. For that, we use
list comprehensions

98. For that, we use
list comprehensions

99. Popquiz!
What do you think is in list now?

100. The original list is not modified

101. The original list is not modified
We can also filter

102. The original list is not modified
We can also filter
Beware, filter is on x!

107. This is just a string

108. This is just a string
but we can put data in to format it