Date range search

This page describes how you can search by date with date range search. As well it describes the creation of date wise search queries, and also describes the management of formats for date range search.

Creating date range search queries

Date range search allows you to search in documents dates from a given range in given date formats.

Queries for date range search in text form are specified in the following format:

  • daterange( date ~~ date )

where date is the date in yyyy-MM-dd format, for example, 2019-09-13. Please note that in a search query, dates are always set in the same format.

The following example demonstrates how to search by date using queries in text and object form.

C#

string indexFolder = @"c:\MyIndex\";
string documentsFolder = @"c:\MyDocuments\";
 
// Creating an index in the specified folder
Index index = new Index(indexFolder);
 
// Indexing documents from the specified folder
index.Add(documentsFolder);
 
// Search for dates using query in text form
string query1 = "daterange(2017-01-01 ~~ 2019-12-31)";
SearchResult result1 = index.Search(query1);
 
// Search for dates using query in text form
SearchQuery query2 = SearchQuery.CreateDateRangeQuery(new DateTime(2017, 1, 1), new DateTime(2019, 12, 31));
SearchResult result2 = index.Search(query2);

Specifying date range search formats

To perform the date range search, the date templates specified in the search options are used. The following formats are used by default:

  • dd.MM.yyyy
  • MM/dd/yyyy
  • yyyy-MM-dd

Formats for date range search are set in the DateFormats property of the SearchOptions class. To add a format, use the Add method, to remove it, use the Remove method, to clear a collection of existing formats, use the Clear method. Each format in the collection is defined by an instance of the DateFormat class. To create a new format, you must specify a sequence of format elements and a separator character. All available format elements are represented in the DateFormatElement class:

  • DayOfMonth specifies the day of month element, represented by one or two digits;
  • DayOfMonthTwoDigits specifies the day of month element, represented by two digits;
  • Month specifies the month element, represented by one or two digits;
  • MonthTwoDigits specifies the month element, represented by two digits;
  • MonthAbbreviatedName specifies the month element, represented by abbreviated name;
  • MonthFullName specifies the month element, represented by full name;
  • Year specifies the year element, represented by one, two, three, or four digits;
  • YearTwoDigits specifies the year element, represented by two digits;
  • YearFourDigits specifies the year element, represented by four digits;
  • DateSeparator specifies the date separator element.

An example of setting the date format for the search is presented below.

C#

string indexFolder = @"c:\MyIndex\";
string documentsFolder = @"c:\MyDocuments\";
 
// Creating an index in the specified folder
Index index = new Index(indexFolder);
 
// Indexing documents from the specified folder
index.Add(documentsFolder);
 
// Setting date formats
SearchOptions options = new SearchOptions();
options.DateFormats.Clear(); // Removing default date formats
DateFormatElement[] elements = new DateFormatElement[]
{
    DateFormatElement.MonthTwoDigits,
    DateFormatElement.DateSeparator,
    DateFormatElement.DayOfMonthTwoDigits,
    DateFormatElement.DateSeparator,
    DateFormatElement.YearFourDigits,
};
// Creating a date format pattern 'MM/dd/yyyy'
DateFormat dateFormat = new DateFormat(elements, "/");
options.DateFormats.Add(dateFormat);
 
// Searching in the index.
// For the given query, for example, the date 09/27/2019 will be found,
// but the date 2019-09-27 will not be found, because it is presented in a format that is not specified in the search options.
SearchResult result = index.Search("daterange(2017-01-01 ~~ 2019-12-31)", options);

More resources

GitHub examples

You may easily run the code from documentation articles and see the features in action in our GitHub examples:

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