72 lines
1.5 KiB
Markdown
72 lines
1.5 KiB
Markdown
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# Exercise 8.3 - Solution
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```python
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# coticker.py
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from structure import Structure
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from validate import String, Integer, Float
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class Ticker(Structure):
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name = String()
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price = Float()
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date = String()
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time = String()
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change = Float()
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open = Float()
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high = Float()
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low = Float()
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volume = Integer()
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from cofollow import consumer, follow
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from tableformat import create_formatter
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import csv
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# Coroutine that splits rows using the CSV module. This is rather
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# mind-bending due to the fact that the csv module only understands
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# iteration with the for-loop. To make it work, we wrap it around
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# a generator that simply produces the last item received.
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@consumer
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def to_csv(target):
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def producer():
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while True:
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yield line
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reader = csv.reader(producer())
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while True:
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line = yield
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target.send(next(reader))
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@consumer
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def create_ticker(target):
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while True:
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row = yield
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target.send(Ticker.from_row(row))
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@consumer
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def negchange(target):
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while True:
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record = yield
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if record.change < 0:
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target.send(record)
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@consumer
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def ticker(fmt, fields):
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formatter = create_formatter(fmt)
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formatter.headings(fields)
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while True:
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rec = yield
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row = [getattr(rec, name) for name in fields]
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formatter.row(row)
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if __name__ == '__main__':
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follow('Data/stocklog.csv',
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to_csv(
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create_ticker(
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negchange(
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ticker('text', ['name','price','change'])))))
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```
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[Back](ex8_3.md)
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