Log analyser

Write the codeHard 3 stages

Launch day produced a long mission log, and the post-flight review starts in an hour. Nobody will read every line. The review board wants three answers: how busy was each hour and level, what went wrong first, and which subsystem complained the most.

Build the analyser that answers them, one stage at a time.

Split each line into its time, level, subsystem and message with split(maxsplit=3), so the message stays whole, and keep them as dicts in entries, with the time as "HH:MM:SS". Then count the entries per level, most common first, and per hour, in time order:

By level:
  WARN: 6
  INFO: 5
  ERROR: 2
By hour:
  09:00: 4
  10:00: 4
  11:00: 5

Two Counters do the counting; the hour is the first two characters of the time, plus ":00".

Levels and hours

Parsed entries

Finish stage 1 to unlock this stage.

Find the first ERROR entry and print its time, subsystem and message, or No ERROR entries when there are none:

First ERROR: 10:14:47 PROP Fuel valve 2 not responding

Stop the loop with break as soon as you find it. The hidden tests also run a log without any errors.

The first ERROR

Finish stage 2 to unlock this stage.

Rank the subsystems by how many WARN entries they raised, numbered from 1:

Warnings by subsystem:
  1. POWER: 3
  2. GNC: 2
  3. COMMS: 1

enumerate(warnings.most_common(), start=1) gives the rank and each (subsystem, count) pair; unpack them as rank, (subsystem, count).

The ranking

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Hints

Iterating Over Dictionary

iterating-over-dictionary.py

# How long a single day lasts on each planet, measured in Earth hours
day_hours = {
    "Mercury": 1408,
    "Venus": 5832,
    "Earth": 24,
    "Mars": 24.6,
    "Jupiter": 9.9,
}

# A plain for loop walks the keys
for planet in day_hours:
    print("Planet:", planet)

# .values() walks the values instead
total = 0
for hours in day_hours.values():
    total = total + hours
print("All five days added together:", total, "hours")

# .items() hands you the key and the value at the same time
for planet, hours in day_hours.items():
    print(f"{planet}: one day is {round(hours / 24, 2)} Earth days")

# sorted() walks the same keys in a different order
for planet in sorted(day_hours):
    print(planet, "->", day_hours[planet], "hours")

Open the full example

script.py

PythonLn 1, Col 1Spaces: 4

Loading the Python environment…

Command-line arguments (sys.argv)

Separate arguments with commas. They're passed on every Run as sys.argv[1:].