Sync

Task/Substring/REXX/substring.rexx

@@ -1,20 +1,37 @@
 /*REXX program demonstrates various ways to extract substrings from a string of characters.  */
-s='abcdefghijk';  n=4;  m=3   /*define come REXX constants (string, index, length of string).*/
-say 'original string:' s      /* [↑]   M   can be  zero    (which indicates a null string).  */
+s='abcdefghijk';  n=4;  m=3   /*define some REXX constants (string, index, length of string).*/
+say 'original string='s       /* [↑]   M   can be  zero    (which indicates a null string).  */
+                              say '──────────────────────────────────────────────────────────1'
 
 u=substr(s,n,m)               /*starting from  N  characters in and of  M  length.           */
 say u
+parse var s =(n) a +(m)       /*another way of doing the above by using the PARSE instruction*/
+say a
+                              say '──────────────────────────────────────────────────────────2'
 
 u=substr(s,n)                 /*starting from  N  characters in,  up to the end-of-string.   */
 say u
+parse var s =(n) a            /*another way of doing the above by using the PARSE instruction*/
+say a
+                              say '──────────────────────────────────────────────────────────3'
 
 u=substr(s,1,length(s)-1)          /*OK:     the whole string  except  the last character.   */
-u=substr(s,1,max(0,length(s)-1))   /*better: this version handles the case of a null string. */
 say u
+v=substr(s,1,max(0,length(s)-1))   /*better: this version handles the case of a null string. */
+say v
+L=length(s) - 1
+parse var s a +(L)            /*another way of doing the above by using the PARSE instruction*/
+say a
+                              say '──────────────────────────────────────────────────────────4'
 
-u=substr(s,pos('def',s),m)    /*starting from a known char   within the string & of M length.*/
+u=substr(s,pos('g',s),m)      /*starting from a known char   within the string & of M length.*/
 say u
+parse var s 'g' a +(m)        /*another way of doing the above by using the PARSE instruction*/
+say a
+                              say '──────────────────────────────────────────────────────────5'
 
-u=substr(s,pos('g',s),m)      /*starting from a known substr within the string & of M length.*/
+u=substr(s,pos('def',s),m)    /*starting from a known substr within the string & of M length.*/
 say u
+parse var s 'def' a +(m)      /*another way of doing the above by using the PARSE instruction*/
+say a
                               /*stick a fork in it sir, we're all done and Bob's your uncle. */