Count log lines by level
A log summariser reports how many lines came in at each level. The level is the first word on the line, and the file is not always tidy.
- The level is the first whitespace-separated word, reported in upper case.
- Lines that are empty or only whitespace are skipped.
- Levels that never appear are not in the result.
countByLevel(lines: list<string>) → map<string, int>
Java needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
Map<String, Integer> countByLevel(List<String> lines) {
}Worked examples
| Call | Result |
|---|---|
countByLevel(Main.<String>ls("ERROR disk full", "warn retrying", "ERROR timeout")) | Main.<String, Integer>mp("ERROR", 2, "WARN", 1) |
countByLevel(Main.<String>ls("INFO ok")) | Main.<String, Integer>mp("INFO", 1) |
countByLevel(Main.<String>ls("", " ")) | Main.<String, Integer>mp() |
countByLevel(Main.<String>ls("DEBUG")) | Main.<String, Integer>mp("DEBUG", 1) |
Hint
Trim the line, take everything up to the first space, upper-case it.
Reference solution in Java
Map<String, Integer> countByLevel(List<String> lines) {
Map<String, Integer> result = new LinkedHashMap<>();
for (String line : lines) {
String t = line.trim();
if (t.isEmpty()) continue;
String level = t.split("\\s+")[0].toUpperCase();
result.merge(level, 1, Integer::sum);
}
return result;
}