| """1. Extractor: finds each number + unit in a question and converts it to SI, with a regex. |
| |
| extract("A car at 70 mph brakes at 0.7g") |
| -> [{"surface": "70 mph", "dimension": "speed", "si": 31.29, "span": (9, 15)}, ...] |
| |
| Only the units in UNITS are read; a number without one of them is ignored. |
| """ |
|
|
| import re |
|
|
| |
| UNITS = { |
| "mph": ("speed", 0.44704), "km/h": ("speed", 1 / 3.6), "kph": ("speed", 1 / 3.6), "m/s": ("speed", 1.0), |
| "m/s²": ("acceleration", 1.0), "m/s2": ("acceleration", 1.0), "g": ("acceleration", 9.80665), |
| "s": ("time", 1.0), "seconds": ("time", 1.0), "min": ("time", 60.0), "minutes": ("time", 60.0), |
| "hours": ("time", 3600.0), |
| "m": ("distance", 1.0), "metres": ("distance", 1.0), "km": ("distance", 1000.0), "miles": ("distance", 1609.344), |
| "kg": ("mass", 1.0), "tonnes": ("mass", 1000.0), |
| "N": ("force", 1.0), "kN": ("force", 1000.0), |
| } |
| |
| QUANTITY = re.compile(r"(\d[\d,]*(?:\.\d+)?)\s*(" + "|".join(re.escape(u) for u in sorted(UNITS, key=len, reverse=True)) |
| + r")(?![\w/²])") |
|
|
|
|
| def extract(text): |
| out = [] |
| for match in QUANTITY.finditer(text): |
| dimension, factor = UNITS[match.group(2)] |
| out.append({"surface": match.group(0), "dimension": dimension, |
| "si": float(match.group(1).replace(",", "")) * factor, "span": match.span()}) |
| return out |
|
|
|
|
| def mask(text, quantities): |
| """The question as the reader sees it: each value replaced by a marker, e.g. "A car at <speed1> brakes". |
| |
| Speeds are numbered in order, so the reader can say which is the start and which the final speed. |
| """ |
| out, pos, speeds = "", 0, 0 |
| for q in quantities: |
| start, end = q["span"] |
| speeds += q["dimension"] == "speed" |
| out += text[pos:start] + (f"<speed{speeds}>" if q["dimension"] == "speed" else f"<{q['dimension']}>") |
| pos = end |
| return out + text[pos:] |
|
|
