Concept Conditionals Add Files (#2430)

* Created about, introduction and links files.

* Added authors and blurb info for conditionals concept.

* Created about, introduction and links files.

* Added authors and blurb info for conditionals concept.

* Apply suggestions from code review

Applied suggestions/edits/corrections from code review.

Co-authored-by: Tim Austin <[email protected]>

* Apply suggestions from code review

Applied suggestions/edits/corrections from code review.

* Attempted to remove hidden CLRF chars in code example.  May have failed.

Co-authored-by: Tim Austin <[email protected]>

concepts/conditionals/.meta/config.json

@@ -1,5 +1,5 @@
 {
-  "blurb": "TODO: add blurb for this concept",
-  "authors": ["bethanyg", "cmccandless"],
+  "blurb": "The conditionals 'if', 'elif' ('else + if'), and 'else' are used to control the flow of execution and make decisions in a program. Python doesn't have a formal case-switch statement ,and uses multiple 'elif's to serve a similar purpose. Conditionals pair with expressions and objects that must resolve to 'True' or 'False'.",
+  "authors": ["bethanyg", "sachsom95"],
   "contributors": []
 }

concepts/conditionals/about.md

@@ -1,2 +1,158 @@
-#TODO: Add about for this concept.
+# About
 
+In Python, [`if`][if statement], `elif` (_a contraction of 'else and if'_) and `else` statements are used in Python to [control the flow][control flow tools] of execution and make decisions in a program.
+Unlike many other programming languages, Python versions 3.9 and below do not offer a formal case-switch statement, instead using multiple `elif` statements to serve a similar purpose.
+
+Python 3.10 introduces a variant case-switch statement called `pattern matching`, which will be covered separately in another concept.
+
+Conditional statements use expressions that must resolve to `True` or `False` -- either by returning a `bool` directly, or by evaluating ["truthy" or "falsy"][truth value testing].
+
+
+
+```python
+x = 10
+y = 5
+
+# The comparison '>' returns the bool 'True',
+# so the statement is printed.
+if x > y:
+    print("x is greater than y")
+...
+>>> x is greater than y
+```
+
+When paired with `if`, an optional `else` code block will execute when the original `if` condition evaluates to `False`:
+
+```python
+x = 5
+y = 10
+
+# The comparison '>' here returns the bool False,
+# so the 'else' block is executed instead of the 'if' block.
+if x > y:
+    print("x is greater than y")
+else:
+    print("y is greater than x")
+...
+>>> y is greater than x
+```
+
+`elif` allows for multiple evaluations/branches.
+
+```python
+x = 5
+y = 10
+z = 20
+
+# The elif statement allows for the checking of more conditions.
+if x > y:
+    print("x is greater than y and z")
+elif y > z:
+    print("y is greater than x and z")
+else:
+    print("z is great than x and y")
+...
+>>> z is great than x and y
+```
+
+[Boolen operations][boolean operations] and [comparisons][comparisons] can be combined with conditionals for more complex testing:
+
+```python
+
+>>> def classic_fizzbuzz(number):
+        if number % 3 == 0 and number % 5 == 0:
+            return 'FizzBuzz!'
+        elif number % 5 == 0:
+            return 'Buzz!'
+        elif number % 3 == 0:
+            return 'Fizz!'
+        else:
+            return str(number)
+
+>>> classic_fizzbuzz(15)
+'FizzBuzz!'
+
+>>> classic_fizzbuzz(13)
+'13'
+```
+
+Conditionals can also be nested.
+
+```python
+>>> def driving_status(driver_age, test_score):
+        if test_score >= 80: 
+            if 18 > driver_age >= 16:
+                return "Student driver, needs supervision."
+            elif driver_age == 18:
+                return "Permitted driver, on probation."
+            elif driver_age > 18:
+                return "Fully licensed driver."
+        else:
+            return "Unlicensed!"
+
+
+>>> driving_status(63, 78)
+'Unlicsensed!'
+
+>>> driving_status(16, 81)
+'Student driver, needs supervision.'
+
+>>> driving_status(23, 80)
+'Fully licsensed driver.'
+```
+
+## Conditional expressions or "ternary operators"
+
+While Python has no specific `?` ternary operator, it is possible to write single-line `conditional expressions`.
+These take the form of `<value if True>` if `<conditional test>` else `<value if False>`.
+Since these expressions can become hard to read, it's recommended to use this single-line form only if it shortens code and helps readability.
+
+
+```python
+def just_the_buzz(number):
+    return 'Buzz!' if number % 5 == 0 else str(number)
+
+>>> just_the_buzz(15)
+'Buzz!'
+
+>>> just_the_buzz(10)
+'10'
+```
+
+## Truthy and Falsy
+
+In Python, any object can be tested for [truth value][truth value testing], and can therefore be used with a conditional, comparison, or boolean operation.
+Objects that are evaluated in this fashion are considered "truthy" or "falsy", and used in a `boolean context`.
+
+```python
+>>> def truthy_test(thing):
+        if thing:
+            print('This is Truthy.')
+        else:
+            print("Nope. It's Falsey.")
+
+
+# Empty container objects are considered Falsey.
+>>> truthy_test([])
+Nope. It's Falsey.
+
+>>> truthy_test(['bear', 'pig', 'giraffe'])
+This is Truthy.
+
+# Empty strings are considered Falsey.
+>>> truthy_test('')
+Nope. It's Falsey.
+
+>>> truthy_test('yes')
+This is Truthy.
+
+# 0 is also considered Falsey.
+>>> truthy_test(0)
+Nope. It's Falsey.
+```
+
+[if statement]: https://docs.python.org/3/reference/compound_stmts.html#the-if-statement
+[control flow tools]: https://docs.python.org/3/tutorial/controlflow.html#more-control-flow-tools
+[truth value testing]: https://docs.python.org/3/library/stdtypes.html#truth-value-testing
+[boolean operations]: https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not
+[comparisons]: https://docs.python.org/3/library/stdtypes.html#comparisons

concepts/conditionals/introduction.md

@@ -1,2 +1,82 @@
-#TODO: Add introduction for this concept.
+# Introduction
 
+In Python, [`if`][if statement], `elif` (_a contraction of 'else and if'_) and `else` statements are used in Python to [control the flow][control flow tools] of execution and make decisions in a program.
+Unlike many other programming languages, Python versions 3.9 and below do not offer a formal case-switch statement, instead using multiple `elif` statements to serve a similar purpose.
+
+Python 3.10 introduces a variant case-switch statement called `pattern matching`, which will be covered separately in another concept.
+
+Conditional statements use expressions that must resolve to `True` or `False` -- either by returning a `bool` directly, or by evaluating ["truthy" or "falsy"][truth value testing].
+
+
+```python
+x = 10
+y = 5
+
+# The comparison '>' returns the bool 'True',
+# so the statement is printed.
+if x > y:
+    print("x is greater than y")
+...
+>>> x is greater than y
+```
+
+When paired with `if`, an optional `else` code block will execute when the original `if` condition evaluates to `False`:
+
+```python
+x = 5
+y = 10
+
+# The comparison '>' here returns the bool False,
+# so the 'else' block is executed instead of the 'if' block.
+if x > y:
+    print("x is greater than y")
+else:
+    print("y is greater than x")
+...
+>>> y is greater than x
+```
+
+`elif` allows for multiple evaluations/branches.
+
+```python
+x = 5
+y = 10
+z = 20
+
+# The elif statement allows for the checking of more conditions.
+if x > y:
+    print("x is greater than y and z")
+elif y > z:
+    print("y is greater than x and z")
+else:
+    print("z is great than x and y")
+...
+>>> z is great than x and y
+```
+
+[Boolen operations][boolean operations] and [comparisons][comparisons] can be combined with conditionals for more complex testing:
+
+```python
+
+>>> def classic_fizzbuzz(number):
+        if number % 3 == 0 and number % 5 == 0:
+            return 'FizzBuzz!'
+        elif number % 5 == 0:
+            return 'Buzz!'
+        elif number % 3 == 0:
+            return 'Fizz!'
+        else:
+            return str(number)
+
+>>> classic_fizzbuzz(15)
+'FizzBuzz!'
+
+>>> classic_fizzbuzz(13)
+'13'
+```
+
+[if statement]: https://docs.python.org/3/reference/compound_stmts.html#the-if-statement
+[control flow tools]: https://docs.python.org/3/tutorial/controlflow.html#more-control-flow-tools
+[truth value testing]: https://docs.python.org/3/library/stdtypes.html#truth-value-testing
+[boolean operations]: https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not
+[comparisons]: https://docs.python.org/3/library/stdtypes.html#comparisons

concepts/conditionals/links.json

@@ -1,18 +1,22 @@
 [
   {
-    "url": "http://example.com/",
-    "description": "TODO:  add new link (above) and write a short description here of the resource."
+    "url": "https://docs.python.org/3/tutorial/controlflow.html#more-control-flow-tools",
+    "description": "Python Docs: Control flow tools."
   },
   {
-    "url": "http://example.com/",
-    "description": "TODO:  add new link (above) and write a short description here of the resource."
+    "url": "https://docs.python.org/3/library/stdtypes.html#truth-value-testing",
+    "description": "Python Docs:  Truth value testing."
   },
   {
-    "url": "http://example.com/",
-    "description": "TODO:  add new link (above) and write a short description here of the resource."
+    "url": "https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not",
+    "description": "Python Docs:  Standard Types - boolean operations."
   },
   {
-    "url": "http://example.com/",
-    "description": "TODO:  add new link (above) and write a short description here of the resource."
+    "url": "https://docs.python.org/3/library/stdtypes.html#comparisons",
+    "description": "Python Docs:  Comparisons."
+  },
+  {
+    "url": "https://realpython.com/python-conditional-statements/",
+    "description": "Real Python:  Conditional statements in Python."
   }
 ]