Run-length encoding: Difference between revisions
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→{{header|Lasso}}: Adding Lasso RLE Example |
→{{header|REXX}}: made incrementing of the DO loop index more idiomatic, changed whitespade and comments, simplified encoding. -- ~~~~ |
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The task (input) rule was relaxed a bit as this program accepts upper- and lowercase input. |
The task (input) rule was relaxed a bit as this program accepts upper- and lowercase input. |
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===encoding=== |
===encoding=== |
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<lang rexx>/*REXX program encodes string by using a run-length scheme |
<lang rexx>/*REXX program encodes a string by using a run-length scheme. */ |
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parse arg x |
parse arg x . /*normally, input would be a file*/ |
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/*═══ arg x . ═══*/ /*◄── use if X must be uppercase.*/ |
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def='WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW' |
def= 'WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW' |
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if x |
if x='' then x=def /*No input? Then use the default.*/ |
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Lx=length(x) /*get the length of the X string.*/ |
Lx=length(x) /*get the length of the X string.*/ |
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y= /*Y is the output string (so far)*/ |
y= /*Y is the output string (so far)*/ |
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do j=1 |
do j=1 by 0 to Lx /*J is incremented (below). */ |
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c=substr(x,j,1) /*pick a character, check for err*/ |
c=substr(x,j,1) /*pick a character, check for err*/ |
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if \datatype(c,' |
if \datatype(c,'M') then do; say "error!: data isn't alphabetic:" c; exit 13; end |
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r=0 /*R is NOT the number of chars. */ |
r=0 /*R is NOT the number of chars. */ |
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end /*k*/ |
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end /*k*/ |
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if r==0 then r= /*don't use R if R is zero.*/ |
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Y = Y || r || c /*add it to the encoded string.*/ |
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end /*j*/ |
end /*j*/ |
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