Text processing/1: Difference between revisions

=={{header|Swift}}==

{{trans|Rust}}

<lang swift>import Foundation

let fmtDbl = { String(format: "%10.3f", $0) }

Task.detached {

let formatter = DateFormatter()

formatter.dateFormat = "yyyy-MM-dd"

let (data, _) = try await URLSession.shared.bytes(from: URL(fileURLWithPath: CommandLine.arguments[1]))

var rowStats = [(Date, Double, Int)]()

var invalidPeriods = 0

var invalidStart: Date?

var sumFile = 0.0

var readings = 0

var longestInvalid = 0

var longestInvalidStart: Date?

var longestInvalidEnd: Date?

for try await line in data.lines {

let lineSplit = line.components(separatedBy: "\t")

guard !lineSplit.isEmpty, let date = formatter.date(from: lineSplit[0]) else {

fatalError("Invalid date \(lineSplit[0])")

}

let data = Array(lineSplit.dropFirst())

let parsed = stride(from: 0, to: data.endIndex, by: 2).map({idx -> (Double, Int) in

let slice = data[idx..<idx+2]

return (Double(slice[idx]) ?? 0, Int(slice[idx+1]) ?? 0)

})

var sum = 0.0

var numValid = 0

for (val, flag) in parsed {

if flag <= 0 {

if invalidStart == nil {

invalidStart = date

}

invalidPeriods += 1

} else {

if invalidPeriods > longestInvalid {

longestInvalid = invalidPeriods

longestInvalidStart = invalidStart

longestInvalidEnd = date

}

sumFile += val

sum += val

numValid += 1

readings += 1

invalidPeriods = 0

invalidStart = nil

}

}

if numValid != 0 {

rowStats.append((date, sum / Double(numValid), parsed.count - numValid))

}

}

for stat in rowStats.lazy.reversed().prefix(5) {

print("\(stat.0): Average: \(fmtDbl(stat.1)); Valid Readings: \(24 - stat.2); Invalid Readings: \(stat.2)")

}

print("""

Sum File: \(fmtDbl(sumFile))

Average: \(fmtDbl(sumFile / Double(readings)))

Readings: \(readings)

Longest Invalid: \(longestInvalid) (\(longestInvalidStart!) - \(longestInvalidEnd!))

""")

exit(0)

}

dispatchMain()

</lang>

{{out}}

<pre>2004-12-31 05:00:00 +0000: Average: 2.057; Valid Readings: 23; Invalid Readings: 1

2004-12-30 05:00:00 +0000: Average: 2.839; Valid Readings: 23; Invalid Readings: 1

2004-12-29 05:00:00 +0000: Average: 2.448; Valid Readings: 23; Invalid Readings: 1

2004-12-28 05:00:00 +0000: Average: 3.383; Valid Readings: 23; Invalid Readings: 1

2004-12-27 05:00:00 +0000: Average: 2.483; Valid Readings: 23; Invalid Readings: 1

Sum File: 1358393.400

Average: 10.497

Readings: 129403

Longest Invalid: 589 (1993-02-09 05:00:00 +0000 - 1993-03-05 05:00:00 +0000)</pre>