Advanced features in the PURECSV framework: CSV data screening, sorting and filtering
PURECSV is a simple and easy -to -use Java CSV file processing framework. It provides many advanced features to process CSV data, including screening, sorting and filtering.This article will introduce these advanced features in the PureCSV framework and provide relevant Java code examples.
1. CSV data screening
In PureCSV, you can use predict to screen the qualified CSV data.The predicate is a function used to determine whether a certain element meets specific conditions.You can write the predicate based on the value, line index or other rules of a column.The following is an example of screening CSV data:
// Create the predicate, screen the line that meets specific conditions
Predicate<CSVRecord> predicate = record -> record.get("年龄").equals("25");
// Read the CSV file
CSVParser parser = CSVParser.parse(new File("data.csv"), Charset.defaultCharset(), CSVFormat.DEFAULT);
// Print the line that meets the conditions
for (CSVRecord record : parser) {
if (predicate.test(record)) {
System.out.println(record);
}
}
In the above code, we created a predicate, through the `record.get (" age ") .equals (" 25 ")` determine whether the value of the "age" column is "25".Then we read the CSV file and traverse each line of data. If the conditions are met, print the line data.
2. CSV data sorting
PURECSV provides the `CSVSORTER` class to sort CSV data.You can choose to sort in the value of a certain column or order.The following is an example:
// Create a CSVSORTER instance, and sort in order of "age" columns
CSVSORTER SORTER = New CSVSORTER ("Age", Sortorder.Descending);
// Read the CSV file
CSVParser parser = CSVParser.parse(new File("data.csv"), Charset.defaultCharset(), CSVFormat.DEFAULT);
// Sort and print the result
List<CSVRecord> sortedRecords = sorter.sort(parser.getRecords());
for (CSVRecord record : sortedRecords) {
System.out.println(record);
}
In the above code, we created a `csvsorter` instance, and specified that the" age "columns were sorted.Then we read the CSV file and use the `sort` method to sort the records.Finally, we traversed the records and printed the results.
3. CSV data filtering
In PureCSV, you can use the `Rowfilter` class to filter CSV data.You can filter records based on the value, line index or other conditions of a column.The following is an example:
// Create a rowfilter instance and specify the filtering rules
RowFilter<CSVRecord> filter = new RowFilter<CSVRecord>() {
@Override
public boolean include(RowFilter.Entry<? extends CSVRecord> entry) {
String value = ENTRY.GetStringValue ("Gender");
return value.equals("男");
}
};
// Read the CSV file
CSVParser parser = CSVParser.parse(new File("data.csv"), Charset.defaultCharset(), CSVFormat.DEFAULT);
// Filter records and print results
FilteredIterator<CSVRecord> filteredIterator = new FilteredIterator<>(parser.iterator(), filter);
while (filteredIterator.hasNext()) {
CSVRecord record = filteredIterator.next();
System.out.println(record);
}
In the above code, we created an instance of `Rowfilter` and filter the records based on the value of the" Gender "column.Then we read the CSV file and use the `FiltereDiterator` class filtering record.Finally, we traverse the records and print the results.
Summarize:
This article introduces the advanced features of the PureCSV framework, including CSV data screening, sorting and filtering.You can use the predicate to screen data, use CSVSORTER to sort the data, and use Rowfilter for data filtering.I hope this article can help you better understand and use these advanced features in the PureCSV framework.
