CHARSORT()
Sort sequences within a string.
- Syntax
-
- CHARSORT (<[@]cString>, [<nElementLength>], [<nCompareLength>],
- [<nIgnoreCharacters>], [<nElemenOffset>], [<nSortLength>],
- [<lDescending>]) -> cSortedString
- Arguments
-
- <[@]cString> is the string that should be processed [<nElementLength>] specifies the length of the elements that should be sorted Default: 1 [<nCompareLength>] specifies how many characters within one element should be used for comparison Default: <nElementLength> [<nIgnoreCharacters>] specifies the number of characters at the beginning of <cString> that should be ignored in the sort process Default: 0 [<nElementOffset>] specifies the offset of the comparison string within a element Default: 0 [<nSortLength>] specifies how many characters in <cString>, starting from the <nIgnoreCharacters> position, should be sorted Default: len(cString)-nIgnoreCharacters [<lDescending>]) specifies whether the process should sort descending or not
- Returns
-
- <cSortedString> the string resulting from the sort process
- Description
-
- The CHARSORT function sorts the characters within a string <cString>. With the parameters <nIgnoreCharacters> and <nSortLength>, you can determine that only the substring from position <nIgnoreCharacters>+1 to position <nIgnoreCharacters>+<nSortLength> within <cString> should be sorted. The sorting algorithm is determined with the other parameters. <nElementLength> specifies the length of one element, i.e. there are <nSortLength>/<nElementLength> elements that are sorted. Note that surplus characters are not sorted but stay at their position. To do the sorting, the function uses the Quicksort algorithm implemented in the C-lib qsort() function. This algorithm needs to know how to compare and order two elements. This is done by comparing the ASCII values of a substring within each element. This substring is determined by the parameters <nElementOffset> and <nCompareLength> and the order by <lDescending>. By setting the CSETREF() switch to .T., one can omit the return value of the function, but one must then pass <cString> by reference.
Examples
? CHARSORT("qwert") // "eqrtw"
? CHARSORT("qwert", 2) // "erqwt"
? CHARSORT("b1a4a3a2a1", 2, 1) // "a2a1a3a4b1"
? CHARSORT("XXXqwert", 1, 1, 3) // "XXXeqrtw"
? CHARSORT("b1a4a3a2a1", 2, 1, 0, 1) // "a1b1a2a3a4"
? CHARSORT("384172852", 1, 1, 0, 0, 4) // "134872852"
? CHARSORT("qwert", .T.) // "wtrqe"
Tests
CHARSORT("qwert") == "eqrtw"
CHARSORT("qwert", 2) == "erqwt"
CHARSORT("b1a4a3a2a1", 2, 1) == "a2a1a3a4b1"
CHARSORT("XXXqwert", 1, 1, 3) == "XXXeqrtw"
CHARSORT("b1a4a3a2a1", 2, 1, 0, 1) == "a1b1a2a3a4"
CHARSORT("384172852", 1, 1, 0, 0, 4) == "134872852"
CHARSORT("qwert", .T.) == "wtrqe"
- Status
- Ready
- Compliance
-
- CHARSORT() is compatible with CT3's CHARSORT().
- Platforms
-
- All
- Files
-
- Source is charsort.c, library is ct3.
- See Also