Update Notes/03_Program_organization/02_More_functions.md

.vscode/settings.json

@@ -0,0 +1,12 @@
+{
+    "python.testing.pytestArgs": [
+        "Work",
+        "--rootdir=Work",
+    ],
+    "python.testing.unittestEnabled": false,
+    "python.testing.pytestEnabled": true,
+    "[python]": {
+        "editor.defaultFormatter": "ms-python.black-formatter"
+    },
+    "python.formatting.provider": "none"
+}

Notes/03_Program_organization/02_More_functions.md

@@ -501,7 +501,7 @@ For example:
 ```python
 >>> portfolio = parse_csv('Data/portfolio.dat', types=[str, int, float], delimiter=' ')
 >>> portfolio
-[{'price': '32.20', 'name': 'AA', 'shares': '100'}, {'price': '91.10', 'name': 'IBM', 'shares': '50'}, {'price': '83.44', 'name': 'CAT', 'shares': '150'}, {'price': '51.23', 'name': 'MSFT', 'shares': '200'}, {'price': '40.37', 'name': 'GE', 'shares': '95'}, {'price': '65.10', 'name': 'MSFT', 'shares': '50'}, {'price': '70.44', 'name': 'IBM', 'shares': '100'}]
+[{'name': 'AA', 'shares': 100, 'price': 32.2}, {'name': 'IBM', 'shares': 50, 'price': 91.1}, {'name': 'CAT', 'shares': 150, 'price': 83.44}, {'name': 'MSFT', 'shares': 200, 'price': 51.23}, {'name': 'GE', 'shares': 95, 'price': 40.37}, {'name': 'MSFT', 'shares': 50, 'price': 65.1}, {'name': 'IBM', 'shares': 100, 'price': 70.44}]
 >>>
 ```
 

Work/Data/stocksim.py

@@ -112,13 +112,23 @@ def update(self):
     def incr(self,dt):
         self.time += dt
         if self.index < (len(self.history) - 2):
-            while self.index < (len(self.history) - 2) and self.time >= self.history[self.index+1][3]:
+            while self.index < (len(self.history) - 2) and \
+                self.time >= self.history[self.index+1][3]:
                 self.index += 1
         self.update()
 
     def make_record(self):
-        return [self.name,round(self.price,2),self.date,minutes_to_str(self.time),round(self.change,2),self.open,round(self.high,2),
-                round(self.low,2),self.volume]
+        return [
+            self.name,
+            round(self.price, 2),
+            self.date,
+            minutes_to_str(self.time),
+            round(self.change, 2),
+            self.open,
+            round(self.high, 2),
+            round(self.low, 2),
+            self.volume
+        ]
 
 class MarketSimulator(object):
     def __init__(self):

Work/bounce.py

@@ -1,3 +1,13 @@
 # bounce.py
 #
 # Exercise 1.5
+
+def bounce():
+    current_height = 100 # meters
+    fall_fraction = 3 / 5 # fraction of from_height
+
+    for i in range(1, 11):
+        current_height *= fall_fraction
+        print(i, round(current_height, 4))
+
+bounce()

Work/bounce_test.py

@@ -0,0 +1,17 @@
+from bounce import bounce
+
+def test_main(capfd):
+    bounce()
+
+    out, err = capfd.readouterr()
+    assert out == """1 60.0
+2 36.0
+3 21.6
+4 12.96
+5 7.776
+6 4.6656
+7 2.7994
+8 1.6796
+9 1.0078
+10 0.6047
+"""

Work/currency.py

@@ -0,0 +1,4 @@
+def usd(value: float) -> str:
+    """Format a number as USD."""
+    neg = '-' if value < 0 else ''
+    return f"{neg}${abs(value):,.2f}"

Work/currency_test.py

@@ -0,0 +1,13 @@
+import pytest
+from currency import usd
+
+@pytest.mark.parametrize("input,output", [
+    (1, "$1.00"),
+    (11.5, "$11.50"),
+    (1.75, "$1.75"),
+    (1200.751, "$1,200.75"),
+    (-1245.758, "-$1,245.76"),
+    (-1.754, "-$1.75")
+])
+def test_usd(input, output):
+    assert usd(input) == output

Work/dowstocks.py

@@ -0,0 +1,20 @@
+import csv
+
+def date_tuple(s):
+    return tuple(str(s).split('/'))
+
+def main():
+    with open('Data/dowstocks.csv') as f:
+        rows = csv.reader(f)
+        headers = next(rows)
+        print(headers)
+        types = [str, float, date_tuple, str, float, float, float, float, int]
+        dow_stocks = [
+            { key: func(val) for key, func, val in zip(headers, types, row) }
+            for row in rows
+        ]
+        print(dow_stocks[0]['date'])
+        print(len(dow_stocks))
+
+if __name__ == '__main__':
+    main()

Work/fileparse.py

@@ -1,3 +1,32 @@
 # fileparse.py
 #
 # Exercise 3.3
+import csv
+
+
+def parse_csv(
+    filename: str,
+    select: list = [],
+    types: list = [],
+    has_headers: bool = True,
+    delimiter: str = ",",
+) -> list:
+    """
+    Parse a CSV file into a list of records
+    """
+    with open(filename) as f:
+        rows = csv.reader(f, delimiter=delimiter)
+        if has_headers:
+            orig_headers = next(rows)
+            headers = select if select else orig_headers
+            indices = [headers.index(name) for name in headers]
+        records = []
+        for orig_row in rows:
+            if not orig_row:
+                continue
+            row = [orig_row[i] for i in indices] if has_headers else orig_row
+            if types:
+                row = [func(field) for func, field in zip(types, row)]
+            record = dict(zip(headers, row)) if has_headers else tuple(row)
+            records.append(record)
+    return records

Work/fileparse_test.py

@@ -0,0 +1,84 @@
+from fileparse import parse_csv
+
+
+def test_parse_csv_select_3_4():
+    assert parse_csv("Data/portfolio.csv", select=["name", "shares"]) == [
+        {"name": "AA", "shares": "100"},
+        {"name": "IBM", "shares": "50"},
+        {"name": "CAT", "shares": "150"},
+        {"name": "MSFT", "shares": "200"},
+        {"name": "GE", "shares": "95"},
+        {"name": "MSFT", "shares": "50"},
+        {"name": "IBM", "shares": "100"},
+    ]
+
+
+def test_parse_csv_select_3_5():
+    assert parse_csv("Data/portfolio.csv", types=[str, int, float]) == [
+        {"price": 32.2, "name": "AA", "shares": 100},
+        {"price": 91.1, "name": "IBM", "shares": 50},
+        {"price": 83.44, "name": "CAT", "shares": 150},
+        {"price": 51.23, "name": "MSFT", "shares": 200},
+        {"price": 40.37, "name": "GE", "shares": 95},
+        {"price": 65.1, "name": "MSFT", "shares": 50},
+        {"price": 70.44, "name": "IBM", "shares": 100},
+    ]
+
+    assert parse_csv(
+        "Data/portfolio.csv", select=["name", "shares"], types=[str, int]
+    ) == [
+        {"name": "AA", "shares": 100},
+        {"name": "IBM", "shares": 50},
+        {"name": "CAT", "shares": 150},
+        {"name": "MSFT", "shares": 200},
+        {"name": "GE", "shares": 95},
+        {"name": "MSFT", "shares": 50},
+        {"name": "IBM", "shares": 100},
+    ]
+
+
+def test_parse_csv_no_headers_3_6():
+    assert parse_csv("Data/prices.csv", types=[str, float], has_headers=False) == [
+        ("AA", 9.22),
+        ("AXP", 24.85),
+        ("BA", 44.85),
+        ("BAC", 11.27),
+        ("C", 3.72),
+        ("CAT", 35.46),
+        ("CVX", 66.67),
+        ("DD", 28.47),
+        ("DIS", 24.22),
+        ("GE", 13.48),
+        ("GM", 0.75),
+        ("HD", 23.16),
+        ("HPQ", 34.35),
+        ("IBM", 106.28),
+        ("INTC", 15.72),
+        ("JNJ", 55.16),
+        ("JPM", 36.9),
+        ("KFT", 26.11),
+        ("KO", 49.16),
+        ("MCD", 58.99),
+        ("MMM", 57.1),
+        ("MRK", 27.58),
+        ("MSFT", 20.89),
+        ("PFE", 15.19),
+        ("PG", 51.94),
+        ("T", 24.79),
+        ("UTX", 52.61),
+        ("VZ", 29.26),
+        ("WMT", 49.74),
+        ("XOM", 69.35),
+    ]
+
+
+def test_parse_csv_delimiter_3_7():
+    assert parse_csv("Data/portfolio.dat", types=[str, int, float], delimiter=" ") == [
+        { "name": "AA", "shares": 100, "price": 32.2 },
+        { "name": "IBM", "shares": 50, "price": 91.1 },
+        { "name": "CAT", "shares": 150, "price": 83.44 },
+        { "name": "MSFT", "shares": 200, "price": 51.23 },
+        { "name": "GE", "shares": 95, "price": 40.37 },
+        { "name": "MSFT", "shares": 50, "price": 65.1 },
+        { "name": "IBM", "shares": 100, "price": 70.44 },
+    ]

Work/hello.py

@@ -0,0 +1 @@
+print('Suh, Dude?')

Work/mortgage.py

@@ -1,3 +1,37 @@
 # mortgage.py
 #
 # Exercise 1.7
+
+def mortgage(extra_payment_start_month=0,
+             extra_payment_end_month=0,
+             extra_payment=0.0):
+    principal = 500000.0
+    rate = 0.05
+    default_payment = 2684.11
+    paid = 0.0
+    month = 0
+
+    print(f'{"Mo":>3} {"Paid":>11} {"Principal":>11}')
+    while principal > 0:
+        month += 1
+        payment = default_payment
+
+        if month >= extra_payment_start_month and month <= extra_payment_end_month:
+            payment += extra_payment
+
+        if payment > principal:
+            payment = principal
+            principal = 0
+        else:
+            principal = principal * (1 + rate / 12) - payment
+
+        paid = paid + payment
+        print(f'{month:>3} {f"${paid:,.2f}":>11} {f"${principal:,.2f}":>11}')
+
+    print('------------------')
+    print(f'Total paid: ${round(paid, 2):,.2f}')
+    print('Months:    ', month)
+    print('------------------')
+    return round(paid, 2)
+
+mortgage(61, 108, 1000)

Work/mortgage_test.py

@@ -0,0 +1,7 @@
+from mortgage import mortgage
+
+def test_mortgage_1_7():
+    assert round(mortgage(), 1) == 966266.9
+
+def test_mortgage_1_8():
+    assert round(mortgage(1, 12, 1000), 2) == 927989.46

Work/pcost.py

@@ -1,3 +1,21 @@
 # pcost.py
 #
 # Exercise 1.27
+import csv
+
+def pcost(filename):
+    '''Returns the total cost of the portfolio'''
+    with open(filename, 'rt') as f:
+        lines = csv.reader(f)
+        cost = 0.0
+        header_line = next(lines)
+        print(header_line)
+        for line_no, line in enumerate(lines):
+            record = dict(zip(header_line, line))
+            try:
+                shares = int(record['shares'])
+                price = float(record['price'])
+                cost += shares * price
+            except ValueError:
+                print(f'Could not parse line {line_no} with data: {line}')
+    return cost

Work/pcost_command.py

@@ -0,0 +1,15 @@
+# Excersize 1.33
+
+from pcost import pcost
+import sys
+
+print(sys.argv)
+print()
+
+if len(sys.argv) > 1:
+    filename = sys.argv[1]
+else:
+    filename = 'Data/portfolio.csv'
+
+cost = pcost(filename)
+print(f'Total cost ${cost:,.2f}')

Work/pcost_test.py

@@ -0,0 +1,13 @@
+from pcost import pcost
+from os import path
+
+data_dir = path.join(path.dirname(__file__), 'Data')
+
+def test_pcost_1_27():
+    assert pcost(path.join(data_dir, 'portfolio.csv')) == 44671.15
+
+def test_pcost_1_31():
+    assert pcost(path.join(data_dir, 'missing.csv')) == 27381.15
+
+def test_pcost_2_16():
+    assert pcost(path.join(data_dir, 'portfoliodate.csv')) == 44671.15