21 lines
997 B
Rexx
21 lines
997 B
Rexx
/*REXX program demonstrates various ways to extract substrings from a string of characters. */
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s='abcdefghijk'; n=4; m=3 /*define come REXX constants (string, index, length of string).*/
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say 'original string:' s /* [↑] M can be zero (which indicates a null string). */
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u=substr(s,n,m) /*starting from N characters in and of M length. */
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say u
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u=substr(s,n) /*starting from N characters in, up to the end-of-string. */
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say u
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u=substr(s,1,length(s)-1) /*OK: the whole string except the last character. */
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u=substr(s,1,max(0,length(s)-1)) /*better: this version handles the case of a null string. */
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say u
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u=substr(s,pos('def',s),m) /*starting from a known char within the string & of M length.*/
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say u
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u=substr(s,pos('g',s),m) /*starting from a known substr within the string & of M length.*/
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say u
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/*stick a fork in it sir, we're all done and Bob's your uncle. */
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