Trimming (computer programming)

In computer programming, trimming (trim) or stripping (strip) is a string manipulation in which leading and trailing whitespace is removed from a string.

For example, the string (enclosed by apostrophes)

would be changed, after trimming, to

Variants

Definition of whitespace

The characters which are considered whitespace varies between programming languages and implementations. For example, C traditionally only counts space, tab, line feed, and carriage return characters, while languages which support Unicode typically include all Unicode space characters. Some implementations also include ASCII control codes (non-printing characters) along with whitespace characters.

Java's trim method considers ASCII spaces and control codes as whitespace, contrasting with the Java isWhitespace() method, which recognizes all Unicode space characters.

Delphi's Trim function considers characters U+0000 (NULL) through U+0020 (SPACE) to be whitespace.

Usage

Following are examples of trimming a string using several programming languages. All of the implementations shown return a new string and do not alter the original variable.

Trim (computing)

A Trim command (known as TRIM in the ATA command set, and UNMAP in the SCSI command set) allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally.

Trim was introduced soon after SSDs were introduced. Because low-level operation of SSDs differs significantly from hard drives, the typical way in which operating systems handle operations like deletes and formats resulted in unanticipated progressive performance degradation of write operations on SSDs. Trimming enables the SSD to handle garbage collection overhead, which would otherwise significantly slow down future write operations to the involved blocks, in advance.

Although tools to "reset" some drives to a fresh state were already available before the introduction of trimming, they also delete all data on the drive, which makes them impractical to use for ongoing optimization. By 2014 many SSDs had internal idle/background garbage collection mechanisms that work independently of trimming; although this successfully maintains their performance even under operating systems that do not support Trim, it has the associated drawbacks of increased write amplification and wear of the flash cells.

Draft (hull)

The draft (American) or draught (British) of a ship's hull is the vertical distance between the waterline and the bottom of the hull (keel), with the thickness of the hull included; in the case of not being included the draft outline would be obtained. Draft determines the minimum depth of water a ship or boat can safely navigate. The draft can also be used to determine the weight of the cargo on board by calculating the total displacement of water and then using Archimedes' principle. A table made by the shipyard shows the water displacement for each draft. The density of the water (salt or fresh) and the content of the ship's bunkers has to be taken into account. The closely related term "trim" is defined as the difference between the forward and aft drafts.

Drafts of a ship

Askø

Askø is a Danish island north of Lolland. It covers an area of 2.82 km² and has 55 inhabitants (as of 1 January 2005).

In 1954, there were 170 inhabitants and one vehicle.

In 2014 energy company SEAS-NVE discovered a Neolithic boat in a submerged settlement as it replaced sea cables by Askø Island. The boat had split and sealing mass consisting of a strip of bark and resin was found in the hole.

See also

Notes

References

Ask (The Smiths song)

"Ask" is a song by The Smiths. It was released as a single in October 1986, reaching No. 14 in the UK Singles Chart. As with most of The Smiths' singles, it was not included on an original album. It can be found on the compilations The World Won't Listen and Louder Than Bombs as well as the live album Rank, where it is introduced as the band's new single. The UK cover shows Yootha Joyce on the set of the 1965 film Catch Us If You Can. The song features Kirsty MacColl on backing vocals. In 1995, the single was reissued, reaching No. 62 in the UK Singles Chart.

There are two versions of this song. The version that appears on the single releases and the album The Very Best of The Smiths fades out slightly sooner and has the vocal track lasting until the end of the song. The backing vocals in this version are also mixed differently and are louder. The version that appears on all albums (save for the one listed above) fades out later (though the end of the track is audible, albeit at a very low level) and has the vocal track ending before the fade begins.

Ask (horse)

Ask (foaled 23 March 2003) is a British Thoroughbred racehorse and sire. Unraced as a two-year-old, he showed some promise as a three-year-old in 2006, winning one minor race and finishing fourth in the St Leger. He improved in the following year despite running only three races: he won the Ormonde Stakes and the Cumberland Lodge Stakes and was narrowly beaten in the Canadian International Stakes. He won the Gordon Richards Stakes in 2008 but reached his peak as a six-year-old in the following year, winning the Yorkshire Cup, Coronation Cup and Prix Royal Oak a well as finishing third in the King George VI and Queen Elizabeth Stakes. After a single, unsuccessful start in 2010 his racing career was ended by injury. He was then retired to become a National Hunt stallion in Ireland.

Background

Ask is a bay horse with a white star and snip bred at the Side Hill Stud in Newmarket by his owner the 11th Duke of Devonshire. He was one of the eighteenth crop of foals sired by Sadler's Wells, who won the Irish 2000 Guineas, Eclipse Stakes and Irish Champion Stakes in 1984 went on to be the Champion sire on fourteen occasions. Ask's dam Request, who failed to win in two races, was owned and bred by Queen Elizabeth II. She was a granddaughter of the Queen's outstanding racemare Highclere, who won the 1000 Guineas and the Prix de Diane in 1974 and whose other descendant include Nashwan, Unfuwain and Deep Impact.