edX python lectures 1-4

.gitignore

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+

.vscode/launch.json

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+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Python: Current File",
+            "type": "python",
+            "request": "launch",
+            "program": "${file}"
+        },
+        {
+            "name": "Python: Attach",
+            "type": "python",
+            "request": "attach",
+            "localRoot": "${workspaceFolder}",
+            "remoteRoot": "${workspaceFolder}",
+            "port": 3000,
+            "secret": "my_secret",
+            "host": "localhost"
+        },
+        {
+            "name": "Python: Terminal (integrated)",
+            "type": "python",
+            "request": "launch",
+            "program": "${file}",
+            "console": "integratedTerminal"
+        },
+        {
+            "name": "Python: Terminal (external)",
+            "type": "python",
+            "request": "launch",
+            "program": "${file}",
+            "console": "externalTerminal"
+        },
+        {
+            "name": "Python: Django",
+            "type": "python",
+            "request": "launch",
+            "program": "${workspaceFolder}/manage.py",
+            "args": [
+                "runserver",
+                "--noreload",
+                "--nothreading"
+            ],
+            "debugOptions": [
+                "RedirectOutput",
+                "Django"
+            ]
+        },
+        {
+            "name": "Python: Flask (0.11.x or later)",
+            "type": "python",
+            "request": "launch",
+            "module": "flask",
+            "env": {
+                "FLASK_APP": "app.py"
+            },
+            "args": [
+                "run",
+                "--no-debugger",
+                "--no-reload"
+            ]
+        },
+        {
+            "name": "Python: Module",
+            "type": "python",
+            "request": "launch",
+            "module": "module.name"
+        },
+        {
+            "name": "Python: Pyramid",
+            "type": "python",
+            "request": "launch",
+            "args": [
+                "${workspaceFolder}/development.ini"
+            ],
+            "debugOptions": [
+                "RedirectOutput",
+                "Pyramid"
+            ]
+        },
+        {
+            "name": "Python: Watson",
+            "type": "python",
+            "request": "launch",
+            "program": "${workspaceFolder}/console.py",
+            "args": [
+                "dev",
+                "runserver",
+                "--noreload=True"
+            ]
+        },
+        {
+            "name": "Python: All debug Options",
+            "type": "python",
+            "request": "launch",
+            "pythonPath": "${config:python.pythonPath}",
+            "program": "${file}",
+            "module": "module.name",
+            "env": {
+                "VAR1": "1",
+                "VAR2": "2"
+            },
+            "envFile": "${workspaceFolder}/.env",
+            "args": [
+                "arg1",
+                "arg2"
+            ],
+            "debugOptions": [
+                "RedirectOutput"
+            ]
+        }
+    ]
+}

.vscode/settings.json

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+{
+    "python.pythonPath": "C:\\ProgramData\\Anaconda3\\python.exe"
+}

edX_CS_intro_Python/Lecture4/Hanoi.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Wed Jun  8 12:31:42 2016
+
+@author: ericgrimson
+"""
+
+def printMove(fr, to):
+    print('move from ' + str(fr) + ' to ' + str(to))
+
+def Towers(n, fr, to, spare):
+    if n == 1:
+        printMove(fr, to)
+    else:
+        Towers(n-1, fr, spare, to)
+        Towers(1, fr, to, spare)
+        Towers(n-1, spare, to, fr)
+
+print(Towers(4, 'P1', 'P2', 'P3'))

edX_CS_intro_Python/Lecture4/Lecture4.py

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+
+# iterate
+def iterPower(base, exp):
+    '''
+    base: int or float.
+    exp: int >= 0
+ 
+    returns: int or float, base^exp
+    '''
+    result  = 1
+    while exp > 0:
+        result *= base
+        exp -= 1
+    return result
+
+iterPower(3,3)
+
+
+# recursion
+def recurPower(base, exp):
+    '''
+    base: int or float.
+    exp: int >= 0
+ 
+    returns: int or float, base^exp
+    '''
+    # Your code here
+    if exp ==0:
+        return 1
+    elif exp == 1:
+        return base
+    else:
+        return base * recurPower(base, exp - 1)
+
+recurPower(3,0)
+
+
+# Greatest common denominator
+# iterate
+def gcdIter(a, b):
+    '''
+    a, b: positive integers
+    
+    returns: a positive integer, the greatest common divisor of a & b.
+    '''
+    # Your code here
+    if a > b:
+        small = b
+        smaller = b
+        large = a
+    else:
+        small = a
+        smaller = a
+        large = b
+
+    while smaller > 0:
+        if large % smaller == 0 and small % smaller == 0:
+            return smaller
+        smaller -= 1
+    return 1
+
+gcdIter(9,12)
+
+
+# Greatest common denominator
+# recursion
+def gcdRecur(a, b):
+    '''
+    a, b: positive integers
+    
+    returns: a positive integer, the greatest common divisor of a & b.
+    '''
+    # Your code here
+    # gcd(a, b) is the same as gcd(b, a % b)
+    if b == 0:
+        return a
+    else:
+        return gcdRecur(b, a % b)
+
+gcdRecur(3,6)
+
+
+
+# Is character in string
+# recursion
+# doesn't fully work; see actual assignment for correct def
+def isIn(char, aStr):
+    '''
+    char: a single character
+    aStr: an alphabetized string
+    
+    returns: True if char is in aStr; False otherwise
+    '''
+    # Your code here    
+    if char == aStr[len(aStr)//2]:
+        return True
+    elif len(aStr) == 1:
+        return False
+    elif char > aStr[len(aStr)//2]:
+        aStr = aStr[len(aStr)//2:len(aStr)]
+        return isIn(char, aStr[len(aStr)//2:len(aStr)])
+    else:
+        aStr = aStr[0:len(aStr//2)]
+        return isIn(char, aStr[0:len(aStr)//2])
+
+
+isIn('a', 'abc')
+
+
+################
+# practice problem
+import math
+def polysum (n, s):
+    area = 0.25 * n * s ** 2 / (math.tan(math.pi / n))
+    perim = n * s
+    ps = round(area + perim ** 2, 4)
+    return ps
+
+polysum(4, 5)
+

edX_CS_intro_Python/Lecture4/fExample.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Fri Jun 10 12:59:05 2016
+
+@author: ericgrimson
+"""
+
+def f( x ):
+    x = x + 1
+    print('in f(x): x =', x)
+    return x
+x = 3
+z = f( x )

edX_CS_intro_Python/Lecture4/fib.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Fri Jun 10 13:06:06 2016
+
+@author: ericgrimson
+"""
+
+def fib(x):
+    """assumes x an int >= 0
+       returns Fibonacci of x"""
+    if x == 0 or x == 1:
+        return 1
+    else:
+        return fib(x-1) + fib(x-2)

edX_CS_intro_Python/Lecture4/findElement.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Fri Jun 10 13:03:44 2016
+
+@author: ericgrimson
+"""
+
+def find_elem_recur(e, L):
+    if L == []:
+        return False
+    elif len(L) == 1:
+        return L[0] == e
+    else:
+        half = len(L)//2
+        if L[half] > e:
+            return find_elem_recur(e, L[:half])
+        else:
+            return find_elem_recur(e, L[half:])
+
+
+print(find_elem_recur(1, [1, 2, 3, 5, 7, 8, 9, 15]))

edX_CS_intro_Python/Lecture4/funcAsArgs.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Wed Jun  8 12:25:20 2016
+
+@author: ericgrimson
+"""
+
+def func_a():
+    print('inside func_a')
+def func_b(y):
+    print('inside func_b')
+    return y
+def func_c(z):
+    print('inside func_c')
+    return z()
+print(func_a())
+print(5 + func_b(2))
+print(func_c(func_a))

edX_CS_intro_Python/Lecture4/gAndHExample.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Fri Jun 10 13:01:06 2016
+
+@author: ericgrimson
+"""
+
+def g(x):
+    def h():
+        x = 'abc'
+    x = x + 1
+    print('in g(x): x =', x)
+    h()
+    return x
+
+x = 3
+z = g(x)