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Read a specific line from a file: Difference between revisions

Read a specific line from a file (view source)

Revision as of 03:20, 17 September 2014

1,429 bytes removed ,  9 years ago
→‎{{header|REXX}}: removed needless boilerplate.
(→‎{{header|Ruby}}: replaced completely using newer methods.)
(→‎{{header|REXX}}: removed needless boilerplate.)
Line 998:
<lang REXX>/*REXX program to read a specific line from a file. */
parse arg fileId n . /*get the user args: fileid n */
if fileID=='' then fileId='JUNK.TXT' /*assume thefileID default: JUNK.TXT */
if n=='' then n=7 /*assume the N default: (n=7) 7 */
L=lines(fileid) /*first, see if the file exists. */
if L ==0 then do; say 'error, fileID not found:' fileId; exit; end
│ q=linein(fileId, n) /*read athe specificNth recordline, num.store */in │Q.*/▼
if n\==1 then call linein fileId,n-1 /*second, read previous rec. to N*/
if when L==0 & qLlength(q)==0 then say 'line' n "not found."▼
L=lines(fileid) /* L = # lines left in the file.*/
q=linein(fileId,n) else say 'file' /*readfileId the Nth line,"record" store in Q.*/ n '=' q
qL=length(q) /*getstick thea lengthfork ofin the record.it, we're done.*/</lang>
<br>
select
▲ when L==0 & qL==0 then say 'line' n "not found."
when L==1 & qL==0 then say 'line' n "has a zero length."
otherwise say 'file' fileId "record" n '=' q
end /*select*/
/*stick a fork in it, we're done.*/
/*┌────────────────────────────────────────────────────────────────────┐
│ ─── Normally, we could just use: ─── │
│ │
▲ │ q=linein(fileId,n) /*read a specific record num. */ │
│ │
│── but LINEIN will just return a null when a record isn't found or│
│ when the fileID doesn't exist, or N is beyond the end-of-file.│
│ │
│── In the case of sparse files, the record may not exist (be null).│
└────────────────────────────────────────────────────────────────────┘*/</lang>
 
=={{header|Ruby}}==
Retrieved from "https://rosettacode.org/wiki/Special:MobileDiff/193806"
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