strindex

Arguments

haystack

a character string. The string where to search occurrences of needle.

needle

a character string or character string vector. The string(s) to search in haystack.

ind

a vector of indexes.

which

a vector of indexes.

"regexp" | "r" flag

Then needle elements are used as regular expressions.

Description

strindex searches indexes where needle(i) is found in haystack.

For each k it exist an i such that part(haystack,ind(k)+(0:length(needle(i))-1)) is the same string than needle(i). If which argument is required it contains these i. When using the third parameter "r", the needle should be a string of regular expression. And then strindex is going to match it with haystack according to the regular express rules.

strindex without regular expression argument is based on Knuth-Morris-Pratt algorithm.

This algorithm is more powerful than that used in Scilab 4.x. In some special case, result can be different.

Example:

// Scilab 5.x

-->[k,w]=strindex('aab',['a','ab'])

w = 1. 1. 2. k = 1. 2. 2.

// Scilab 4.x

-->[k,w]=strindex('aab',['a','ab'])

w = 1. 1. k = 1. 2.

The rules of regular expression are similar to Perl language. For a quick start, see http://perldoc.perl.org/perlrequick.html. For a more in-depth tutorial on, see http://perldoc.perl.org/perlretut.html and for the reference page, see http://perldoc.perl.org/perlre.html

Examples

k=strindex('SCI/demos/scicos','/')
k=strindex('SCI/demos/scicos','SCI/')
k=strindex('SCI/demos/scicos','!')
k=strindex('aaaaa','aa')
k=strindex('SCI/demos/scicos',['SCI','sci'])
[k,w]=strindex('1+3*abc/2.33',['+','-','*','/'])
k=strindex('2' ,'/2(]*)?$\1/' ,'r')

See also

• string — conversion to string
• strings — Scilab Object, character strings
• regexp — in a string, locate (and extract) substrings matching a regular expression
• strsubst — substitute a character string by another in a character string