The filter() method creates a shallow copy of a portion of a given array, filtered down to just the elements from the given array that pass the test implemented by the provided function.
A shallow copy of a portion of the given array, filtered down to just the elements from the given array that pass the test implemented by the provided function. If no elements pass the test, an empty array will be returned.
The filter() method is an iterative method. It calls a provided callbackFn function once for each element in an array, and constructs a new array of all the values for which callbackFn returns a truthy value. Array elements which do not pass the callbackFn test are not included in the new array.
The filter() method is a copying method. It does not alter this but instead returns a shallow copy that contains the same elements as the ones from the original array (with some filtered out). However, the function provided as callbackFn can mutate the array. Note, however, that the length of the array is saved before the first invocation of callbackFn. Therefore:
Note that filter(function, iterable) is equivalent to the generatorexpression (item for item in iterable if function(item)) if function isnot None and (item for item in iterable if item) if function isNone.
Filtered data displays only the rows that meet criteria that you specify and hides rows that you do not want displayed. After you filter data, you can copy, find, edit, format, chart, and print the subset of filtered data without rearranging or moving it.
Using AutoFilter, you can create two types of filters: by a list value or by criteria. Each of these filter types is mutually exclusive for each range of cells or column table. For example, you can filter by a list of numbers, or a criteria, but not by both; you can filter by icon or by a custom filter, but not by both.
For best results, do not mix data types, such as text and number, or number and date in the same column, because only one type of filter command is available for each column. If there is a mix of data types, the command that is displayed is the data type that occurs the most. For example, if the column contains three values stored as number and four as text, the Text Filters command is displayed .
You can quickly filter data based on visual criteria, such as font color, cell color, or icon sets. And you can filter whether you have formatted cells, applied cell styles, or used conditional formatting.
When you filter data, only the data that meets your criteria appears. The data that doesn't meet that criteria is hidden. After you filter data, you can copy, find, edit, format, chart, and print the subset of filtered data.
Filters are additive. This means that each additional filter is based on the current filter and further reduces the subset of data. You can make complex filters by filtering on more than one value, more than one format, or more than one criteria. For example, you can filter on all numbers greater than 5 that are also below average. But some filters (top and bottom ten, above and below average) are based on the original range of cells. For example, when you filter the top ten values, you'll see the top ten values of the whole list, not the top ten values of the subset of the last filter.
In Excel, you can create three kinds of filters: by values, by a format, or by criteria. But each of these filter types is mutually exclusive. For example, you can filter by cell color or by a list of numbers, but not by both. You can filter by icon or by a custom filter, but not by both.
The following example creates a report of Internet sales outside the United States by using a measure that filters out sales in the United States, and then slicing by calendar year and product categories. To create this measure, you filter the table, Internet Sales USD, by using Sales Territory, and then use the filtered table in a SUMX function.
The following table demonstrates the proof of concept for the measure, NON USA Internet Sales, the formula for which is provided in the code section below. The table compares all Internet sales with non- USA Internet sales, to show that the filter expression works, by excluding United States sales from the computation.
When possible, Power Apps will delegate filter and sort operations to the data source and page through the results on demand. For example, when you start an app that shows a Gallery control filled with data, only the first set of records will be initially brought to the device. As the user scrolls, additional data is brought down from the data source. The result is a faster start time for the app and access to very large data sets.
As the user types characters in SearchInput, the results in the gallery are automatically filtered. In this case, the gallery is configured to show records for which the name of the customer (not the name of the company) starts with the sequence of characters in SearchInput. If the user types co in the search box, the gallery shows these results:
The filter() function is used to subset a data frame,retaining all rows that satisfy your conditions.To be retained, the row must produce a value of TRUE for all conditions.Note that when a condition evaluates to NAthe row will be dropped, unlike base subsetting with [.
The filter() function is used to subset the rows of.data, applying the expressions in ... to the column values to determine whichrows should be retained. It can be applied to both grouped and ungrouped data (see group_by() andungroup()). However, dplyr is not yet smart enough to optimise the filteringoperation on grouped datasets that do not need grouped calculations. For thisreason, filtering is often considerably faster on ungrouped data.
Because filtering expressions are computed within groups, they mayyield different results on grouped tibbles. This will be the caseas soon as an aggregating, lagging, or ranking function isinvolved. Compare this ungrouped filtering:
In the ungrouped version, filter() compares the value of mass in each row tothe global average (taken over the whole data set), keeping only the rows withmass greater than this global average. In contrast, the grouped version calculatesthe average mass separately for each gender group, and keeps rows with mass greaterthan the relevant within-gender average.
Filters perform filtering in the doFilter method. Every Filter has access to a FilterConfig object from which it can obtain its initialization parameters, and a reference to the ServletContext which it can use, for example, to load resources needed for filtering tasks. Filters are configured in the deployment descriptor of a web application. Examples that have been identified for this design are: Authentication Filters Logging and Auditing Filters Image conversion Filters Data compression Filters Encryption Filters Tokenizing Filters Filters that trigger resource access events XSL/T filters Mime-type chain Filter Since:Servlet 2.3
Method SummaryAll Methods Instance Methods Abstract Methods Modifier and TypeMethod and Descriptionvoiddestroy()Called by the web container to indicate to a filter that it is being taken out of service.voiddoFilter(ServletRequest request, ServletResponse response, FilterChain chain)The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain.voidinit(FilterConfig filterConfig)Called by the web container to indicate to a filter that it is being placed into service.Method Detailinitvoid init(FilterConfig filterConfig) throws ServletExceptionCalled by the web container to indicate to a filter that it is being placed into service. The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work. The web container cannot place the filter into service if the init method either Throws a ServletException Does not return within a time period defined by the web container Throws:ServletException
doFiltervoid doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletExceptionThe doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed in to this method allows the Filter to pass on the request and response to the next entity in the chain. A typical implementation of this method would follow the following pattern: Examine the request Optionally wrap the request object with a custom implementation to filter content or headers for input filtering Optionally wrap the response object with a custom implementation to filter content or headers for output filtering Either invoke the next entity in the chain using the FilterChain object (chain.doFilter()), or not pass on the request/response pair to the next entity in the filter chain to block the request processing Directly set headers on the response after invocation of the next entity in the filter chain. Throws:IOExceptionServletException
destroyvoid destroy()Called by the web container to indicate to a filter that it is being taken out of service. This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter. This method gives the filter an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the filter's current state in memory.Skip navigation linksOverview
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