COLLATOR_SET_STRENGTH(3)						 1						  COLLATOR_SET_STRENGTH(3)

Collator::setStrength - Set collation strength

	Object oriented style

SYNOPSIS

       public bool Collator::setStrength (int  $strength)

DESCRIPTION

	Procedural style
       bool collator_set_strength (Collator  $coll, int  $strength)

	The  ICU  Collation  Service  supports	many levels of comparison (named "Levels", but also known as "Strengths"). Having these categories
       enables ICU to sort strings precisely according to local conventions. However, by allowing the levels to be selectively employed, searching
       for a string in text can be performed with various matching conditions.

	      o
		 Primary  Level: Typically, this is used to denote differences between base characters (for example, "a" < "b"). It is the strong-
		est difference. For example, dictionaries are divided into different sections by base character. This is also  called  the  level1
		strength.

	      o
		 Secondary  Level: Accents in the characters are considered secondary differences (for example, "as" < "as" < "at"). Other differ-
		ences between letters can also be considered secondary differences, depending on the language. A secondary difference  is  ignored
		when there is a primary difference anywhere in the strings. This is also called the level2 strength.

	      Note

		      Note:  In  some  languages (such as Danish), certain accented letters are considered to be separate base characters. In most
		     languages, however, an accented letter only has a secondary difference from the unaccented version of that letter.

	      o
		 Tertiary Level: Upper and lower case differences in characters are distinguished at the tertiary level (for example, "ao" <  "Ao"
		<  "ao"). In addition, a variant of a letter differs from the base form on the tertiary level (such as "A" and " "). Another exam-
		ple is the difference between large and small Kana. A tertiary difference is ignored when there is a primary or secondary  differ-
		ence anywhere in the strings. This is also called the level3 strength.

	      o
		 Quaternary  Level:  When punctuation is ignored (see Ignoring Punctuations ) at level 13, an additional level can be used to dis-
		tinguish words with and without punctuation (for example, "ab" < "a-b" < "aB"). This difference is ignored when there  is  a  pri-
		mary,  secondary  or  tertiary	difference. This is also known as the level4 strength. The quaternary level should only be used if
		ignoring punctuation is required or when processing Japanese text (see Hiragana processing).

	      o
		 Identical Level: When all other levels are equal, the identical level is used as a tiebreaker. The Unicode code point	values	of
		the NFD form of each string are compared at this level, just in case there is no difference at levels 14. For example, Hebrew can-
		tillation marks are only distinguished at this level. This level should be used sparingly, as only code point  values  differences
		between two strings is an extremely rare occurrence. Using this level substantially decreases the performance for both incremental
		comparison and sort key generation (as well as increasing the sort key length). It is also known as level 5 strength.

	For example, people may choose to ignore accents or ignore accents and case when searching for text. Almost  all  characters  are  distin-
       guished by the first three levels, and in most locales the default value is thus Tertiary. However, if Alternate is set to be Shifted, then
       the Quaternary strength can be used to break ties among whitespace, punctuation, and symbols that would otherwise be ignored. If very  fine
       distinctions  among characters are required, then the Identical strength can be used (for example, Identical Strength distinguishes between
       the Mathematical Bold Small A and the Mathematical Italic Small A.). However, using levels higher  than	Tertiary  the  Identical  strength
       result in significantly longer sort keys, and slower string comparison performance for equal strings.

PARAMETERS

	      o $coll
		-Collator object.

	      o $strength
		-Strength to set. Possible values are:

		     o Collator::PRIMARY

		     o Collator::SECONDARY

		     o Collator::TERTIARY

		     o Collator::QUATERNARY

		     o Collator::IDENTICAL

		     o Collator::DEFAULT_STRENGTH

RETURN VALUES

	Returns TRUE on success or FALSE on failure.

EXAMPLES

       Example #1

	      collator_set_strength(3) example

	      <?php
	      $arr  = array( 'ao', 'Ao', 'ao' );
	      $coll = collator_create( 'en_US' );

	      // Sort array using default strength.
	      collator_sort( $coll, $arr );
	      var_export( $arr );

	      // Sort array using primary strength.
	      collator_set_strength( $coll, Collator::PRIMARY );
	      collator_sort( $coll, $arr );
	      var_export( $arr );
	      ?>

	      The above example will output:

	      array (
		0 => 'ao',
		1 => 'Ao',
		2 => 'ao',
	      )
	      array (
		0 => 'ao',
		1 => 'Ao',
		2 => 'ao',
	      )

SEE ALSO

       Collator constants, collator_get_strength(3).

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