strrindx#
Purpose#
Finds the index of one string within another string. Searches from the end of the string to the beginning.
Format#
- idx = strrindx(haystack, needle[, start])#
- Parameters:
haystack (string or scalar) – the string, string array or dataframe to be searched.
needle (string or scalar) – the substring to be searched for in haystack.
start (scalar) – the starting point of the search in haystack for an occurrence of needle. haystack will be searched from this point backward for needle. Default is the end of the string
- Returns:
idx (scalar) – contains the index of the last occurrence of needle, within haystack, which is less than or equal to start. If no occurrence is found, it will be 0.
Examples#
// Create a 3x1 string array
state = "alaska" $|
"alabama" $|
"arkansas";
// Find the first instance of the
// letter 'a' starting from
// the end of the string
strrindx(state, "a");
Since the search starts from the back, the above code will print out:
6.0000000
7.0000000
7.0000000
// Find the first instance of the
// letter 'a' starting from the
// 5th character of the string
strrindx(state, "a", 5);
This time, the search will start from the 5th character and continue searching towards the first character, resulting in:
3.0000000
5.0000000
4.0000000
A negative value for start causes the search to begin at the end of the
string. An example of the use of strrindx() is extracting a file name from
a complete path specification:
path = "/gauss/src/ols.src";
ps = "/";
pos = strrindx(path, ps, -1);
if pos;
name = strsect(path, pos+1, strlen(path)-pos);
else;
name = "";
endif;
The above code makes the following assignments:
pos = 11
name = ols.src