Programmer Guide/Command Reference/SUBSTR: Difference between revisions
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{{DISPLAYTITLE:{{SUBPAGENAME}}}} | {{DISPLAYTITLE:{{SUBPAGENAME}}}} | ||
{{PG_StringCommands}} | |||
<var>var</var> := SUBSTR <var>string</var> [ <var>skip_count</var> [ <var>length</var> ]] | |||
The {{STX}} <code>SUBSTR</code> command extracts a substring from its first argument, <var>string</var>. The start of the substring to extract is denoted by the second parameter <var>skip_count</var>, denoting the number of characters ''to skip''. | |||
The length of the substring to extract is denoted by the third parameter, <var>length</var>. If you supply a negative number for <var>length</var>, its absolute value will be used, ''and'' <var>skip_count</var> will start at the ''end'' of the string. Isn't {{STx}} a splendid beast! | |||
The length of the substring to extract is denoted by the third parameter, <var>length</var>. If you supply a negative number for <var>length</var>, its absolute value will be used, ''and'' <var>skip_count</var> will start at the ''end'' of the string. | |||
;<var>string</var> | ;<var>string</var> | ||
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# skip 1 character, returning 'bcd' | # skip 1 character, returning 'bcd' | ||
#str := substr 'abcd' 1 | <var>#str</var> := substr 'abcd' 1 | ||
# skip 2 characters, returning 'cd' | # skip 2 characters, returning 'cd' | ||
#str := substr 'abcd' 2 | <var>#str</var> := substr 'abcd' 2 | ||
# skip 1 character, request 2 characters - returning 'bc' | # skip 1 character, request 2 characters - returning 'bc' | ||
#str := substr 'abcd' 1 2 | <var>#str</var> := substr 'abcd' 1 2 | ||
# skip | # skip 2 character from the end, request 1 character, returning 'b' | ||
#str := substr 'abcd' 1 | <var>#str</var> := substr 'abcd' 2 -1 | ||
Latest revision as of 10:19, 4 March 2016
var := SUBSTR string [ skip_count [ length ]]
The STx SUBSTR command extracts a substring from its first argument, string. The start of the substring to extract is denoted by the second parameter skip_count, denoting the number of characters to skip.
The length of the substring to extract is denoted by the third parameter, length. If you supply a negative number for length, its absolute value will be used, and skip_count will start at the end of the string. Isn't STx a splendid beast!
- string
- The string from which to retrieve the substring.
- skip_count
- by denoting the number of characters to skip from the beginning (length≥0) or from the end of the string (length<0), skip_count indicates where to start extracting the substring. The default value is
0. - length
- Its absolute value determines the length of the substring to extract. If length is less than zero, skip_count characters will be skipped from the end of the string; otherwise, they will be skipped from the beginning of the string. If omitted, the "remaining" part of the string will be extracted.
# skip 1 character, returning 'bcd' #str := substr 'abcd' 1 # skip 2 characters, returning 'cd' #str := substr 'abcd' 2 # skip 1 character, request 2 characters - returning 'bc' #str := substr 'abcd' 1 2 # skip 2 character from the end, request 1 character, returning 'b' #str := substr 'abcd' 2 -1
