Editing

Author: dabeaz

Notes/01_Introduction/01_Python.md

@@ -1,3 +1,5 @@
+[Contents](../Contents) \| [Next (1.2 A First Program)](02_Hello_world)
+
 # 1.1 Python
 
 ### What is Python?
@@ -67,7 +69,7 @@ share. Today, shares of Google are priced at $711.25. Using Python’s
 interactive mode as a calculator, figure out how much profit Larry would
 make if he sold all of his shares.
 
-```pycon
+```python
 >>> (711.25 - 235.14) * 75
 35708.25
 >>>
@@ -77,7 +79,7 @@ Pro-tip: Use the underscore (\_) variable to use the result of the last
 calculation. For example, how much profit does Larry make after his evil
 broker takes their 20% cut?
 
-```pycon
+```python
 >>> _ * 0.80
 28566.600000000002
 >>>
@@ -117,7 +119,7 @@ run, you may have to hit "Return" once after you’ve pasted it in.
 
 Use cut-and-paste to execute the Python statements in this session:
 
-```pycon
+```python
 >>> 12 + 20
 32
 >>> (3 + 4
@@ -147,7 +149,7 @@ Try something more advanced and type these statements to find out how
 long people waiting on the corner of Clark street and Balmoral in
 Chicago will have to wait for the next northbound CTA \#22 bus:
 
-```pycon
+```python
 >>> import urllib.request
 >>> u = urllib.request.urlopen('http://ctabustracker.com/bustime/map/getStopPredictions.jsp?stop=14791&route=22')
 >>> from xml.etree.ElementTree import parse
@@ -176,7 +178,7 @@ If your work environment requires the use of an HTTP proxy server, you may need
 to set the `HTTP_PROXY` environment variable to make this part of the
 exercise work. For example:
 
-```pycon
+```python
 >>> import os
 >>> os.environ['HTTP_PROXY'] = 'http://yourproxy.server.com'
 >>>

Notes/01_Introduction/02_Hello_world.md

@@ -1,3 +1,5 @@
+[Contents](../Contents) \| [Previous (1.1 Python)](01_Python) \| [Next (1.3 Numbers)](03_Numbers)
+
 # 1.2 A First Program
 
 This section discusses the creation of your first program, running the
@@ -46,19 +48,24 @@ hello world
 >>>
 ```
 
-This so-called *read-eval* loop is very useful for debugging and exploration.
+This so-called *read-eval-print-loop* (or REPL) is very useful for debugging and exploration.
 
-Let's take a closer look at the elements:
+**STOP**: If you can't figure out how to interact with Python, stop what you're doing
+and figure out how to do it.  If you're using an IDE, it might be hidden behind a 
+menu option or other window.  Many parts of this course assume that you can
+interact with the interpreter.
+
+Let's take a closer look at the elements of the REPL:
 
 - `>>>` is the interpreter prompt for starting a new statement.
 - `...` is the interpreter prompt for continuing a statements. Enter a blank line to finish typing and run the statements.
 
-The `...` prompt may or may not be shown depending on how you are using Python.  For this course,
+The `...` prompt may or may not be shown depending on your environment. For this course,
 it is shown as blanks to make it easier to cut/paste code samples.
 
 The underscore `_` holds the last result. 
 
-```pycon
+```python
 >>> 37 * 42
 1554
 >>> _ * 2
@@ -94,7 +101,7 @@ bash %
 
 Or from the Windows shell:
 
-```shell
+```
 C:\SomeFolder>hello.py
 hello world
 
@@ -103,6 +110,8 @@ hello world
 ```
 
 Note: On Windows, you may need to specify a full path to the Python interpreter such as `c:\python36\python`.  
+However, if Python is installed in its usual way, you might be able to just type the name of the program
+such as `hello.py`.
 
 ### A Sample Program
 
@@ -134,7 +143,8 @@ print('Final height', num_bills * bill_thickness)
 When you run it, you get the following output:
 
 ```bash
-bash % python3 sears.py 1 1 0.00011
+bash % python3 sears.py
+1 1 0.00011
 2 2 0.00022
 3 4 0.00044
 4 8 0.00088
@@ -197,6 +207,9 @@ height = 442           # Floating point
 height = 'Really tall' # A string
 ```
 
+Python is dynamically typed. The perceived "type" of a variable might change
+as a program executes depending on the current value assigned to it.
+
 ### Case Sensitivity
 
 Python is case sensitive. Upper and lower-case letters are considered different letters.
@@ -228,11 +241,11 @@ while num_bills * bill_thickness < sears_height:
 print('Number of days', days)
 ```
 
-The statements below the `while` will execute as long as the expression after the `while` is `true`.
+The statements indented below the `while` will execute as long as the expression after the `while` is `true`.
 
 ### Indentation
 
-Indentation in Python is used to denote a set of statements that go together.
+Indentation is used to denote groups of statements that go together.
 Consider the previous example:
 
 ```python
@@ -244,17 +257,16 @@ while num_bills * bill_thickness < sears_height:
 print('Number of days', days)
 ```
 
-Indentation groups the following statements together as the operations that 
-execute repeatedly:
+Indentation groups the following statements together as the operations that repeat:
 
 ```python
     print(day, num_bills, num_bills * bill_thickness)
     day = day + 1
     num_bills = num_bills * 2
 ```
 
-Because the `print()` statement at the end is not indented, it means
-that it does not belong to the loop. The empty line is just for
+Because the `print()` statement at the end is not indented, it 
+does not belong to the loop. The empty line is just for
 readability. It does not affect the execution.
 
 ### Indentation best practices
@@ -286,8 +298,6 @@ else:
     print('Computer says yes')
 ```
 
-Depending on the values of `a` and `b`, the execution will jump to `print('Computer says no')` or `print('Computer says yes')`.
-
 You can check for multiple conditions by adding extra checks using `elif`.
 
 ```python
@@ -324,7 +334,7 @@ name = 'Jake'
 print('My name is', name) # Print the text 'My name is Jake'
 ```
 
-`print()` always puts a new line at the end.
+`print()` always puts a newline at the end.
 
 ```python
 print('Hello')
@@ -364,7 +374,7 @@ print('Your name is', name)
 This is useful for small programs, learning exercises or simple debugging.
 It is not widely used for real programs.
 
-### `pass` statement
+### pass statement
 
 Sometimes you need to specify an empty code block. The keyword `pass` is used for it.
 
@@ -379,10 +389,19 @@ This is also called a "no-op" statement. It does nothing. It serves as a placeho
 
 ## Exercises
 
+This is the first set of exercises where you need to create Python
+files and run them.  From this point forward, it is assumed that you
+are editing files in the `practical-python/Work/` directory.  To help
+you locate the proper place, a number of empty starter files have
+been created with the appropriate filenames.  Look for the file
+`Work/bounce.py` that's used in the first exercise.
+
 ### Exercise 1.5: The Bouncing Ball
 
-A rubber ball is dropped from a height of 100 meters and each time it hits the ground, it bounces back up to 3/5 the height it fell.
-Write a program "bounce.py" that prints a table showing the height of the first 10 bounces.
+A rubber ball is dropped from a height of 100 meters and each time it
+hits the ground, it bounces back up to 3/5 the height it fell.  Write
+a program `bounce.py` that prints a table showing the height of the
+first 10 bounces.
 
 Your program should make a table that looks something like this:
 

README.md

@@ -112,3 +112,4 @@ Bug reports are appreciated and may be filed through the [issue
 tracker](https://github.com/dabeaz-course/practical-python/issues).
 Pull requests are not accepted except by invitation.  Please file an
 issue first.
+