Worksheet

F3.6 Records

Strings, lists and records · GCSE · OCR J277 2.2.3, AQA 8525 3.2.6, Edexcel 1CP2 6.3.1 · about 15 min

What this lesson is about

Grouping related fields: a sensor reading as a record, and a list of records as a table.

• A record as a dictionary
• A list of records
• Searching a table of records
• Records as their own type

Questions 5 marks in all

1. [1 mark]What makes a record different from an array?

   1. AA record's fields can hold different data types, reached by name
   2. BA record can only hold numbers
   3. CA record is always sorted
   4. DAn array can hold different types, a record cannot

2. [1 mark]What does this program print?

   reading = {"heading": 90, "distance": 51.0}
   reading["heading"] = 180
   print(reading["heading"], reading["distance"])

3. [1 mark]What does this program print?

   log = [{"h": 0, "d": 31}, {"h": 90, "d": 51}, {"h": 180, "d": 15}]
   best = log[0]
   for r in log:
       if r["d"] > best["d"]:
           best = r
   print(best["h"])

4. [1 mark]A robot log stores a time, a heading, a distance and a note for each reading. Which data types suit the fields?

   Tick every answer that is true.

   1. Atime: real
   2. Bheading: integer
   3. Cdistance: real
   4. Dnote: string

5. [1 mark]In a table of records, what is each row?

   1. AOne record
   2. BOne field
   3. COne data type
   4. DOne array index

The task: reading records

The robot is boxed in on three sides. Look in four directions, 90 degrees apart, storing each look as a record with the fields heading and distance in a list. Then print one line per record as heading 0: 31.0 cm, and finally print closest heading: <heading> for the record with the smallest distance.

# the two lines every program starts with: the commands, then the robot
from bugbot import *
connect()

log = []
for i in range(4):
    turn_right(30, angle=90)

Plan your program here, then type it in and press Run.

Do it on the robot
www.bugbotlab.com/learn/f3-6-records/
The simulator checks it and tells you when it passes. Nothing to install, no account.

Challenges

1. Add a time field to each record using clock().
2. Print the log as a table, with the headings lined up using f-string widths like {r['distance']:6}.
3. Store three names and scores as records and print the name with the highest score.