im trying to get minmax values from a csv, but some of the values on the csv is giving me a NumberExpectedException here is the code im using

 private static void minMaxValue(String path) {
        try (Stream<String> stream = Files.lines(Paths.get(path)).skip(1)) {
            DoubleSummaryStatistics statistics = stream
                    .map(s -> s.split(",")[3])
                    .mapToDouble(Double::valueOf)
                    .summaryStatistics();
            System.out.println("Lowest:: "   statistics.getMin());
            System.out.println("Highest:: "   statistics.getMax());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

and the time im running the method i sorrounded it with a try/catch but it stills is not the solution, i want to replace or ignore all special characters, this is the line that give me error:

Brittany Smith,Programme researcher broadcasting/film/video,Sawyer-Nelson,2901,0.98,8913 Mckay Loop Johnfurt CO 90828

                                                               ^

CodePudding user response：

To replace all special characters with emptyString you may achieve easy using:

str = str.replaceAll("[^a-zA-Z0-9]", " "); 

this way, you will have only letters and digits

CodePudding user response：

Since you're asking for a regex that gets rid of special characters, I guess only to leave characters representing a number (-, ., \d), then this is the regex you're looking for:

String s = s.replaceAll("[^\\-\\.\\d]", ""));

CodePudding user response：

Posting on the basis that your actual problem is caused by the wrong number of separators. That of course is speculation since we haven't seen your actual input. The following would avoid an error of that sort but won't help with diagnosis (streams are unhelpful with errors)

private static void minMaxValue(String path) {
    try (Stream<String> stream = Files.lines(Paths.get(path)).skip(1)) {
        DoubleSummaryStatistics statistics = stream
            .map(s -> s.split(","))
            .filter(s -> s.length == 6) // Don't use magic numbers like this ;)
            .map(s -> s[3])
            .mapToDouble(Double::valueOf)
            .summaryStatistics();
        System.out.println("Lowest:: "   statistics.getMin());
        System.out.println("Highest:: "   statistics.getMax());
    } catch (IOException e) {
        e.printStackTrace();
    }
}