Re^7: Offset Reading

This seems to work:

C:\test>type junk.dat
a_12_3_5- k_3_4_6-a_12_3_5-
q_1_5_7_9- q_1_5_7_9-
a_9_4_5-c_3_4_6- c_3_4_6-r_4_5_7-
b_1_1_3- v_1_5_7-
d_12_4_5-e_4_5_6- g_5_6_7-d_6_8_6-
b_1_1_7-f_3_8_7_8-d_4_1_4- d_4_1_5-b_1_1_7-f_3_8_3
b_1_1_7-f_3_8_7_8-d_4_1_4- e_3_3_1-f_3_8_7-f_21_3_1-b_1_1_7-a_1_1_1-

C:\test>perl -swple"BEGIN{open BIG};($o,$s)=split;seek(BIG,$o,0);read(
+BIG,$_,$s)" -- -BIG=junk.dat con >junk2.dat
1 10
20 10
5 10
30 20
^Z

C:\test>type junk2.dat
_12_3_5- k
12_3_5-
q_
3_5- k_3_4
_1_5_7_9- q_1_5_7_9-
[download]

I leave it to you to work out why yours doesn't.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

RIP Neil Armstrong

Comment on Re^7: Offset Reading - two files Download Code

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Re^8: Offset Reading - two files by gio001 (Acolyte) on Dec 14, 2012 at 16:14 UTC
I will try to work this out, the difference I see is that my input BIG file is a 'single' record, there are no record separator in it, each 'record' is identified by offset and length from the index file, somewhat different from what you illustrated. Is the seek command behaving differently in my case? I even tried: `perl -sple 'BEGIN{open BIG};($1,$2)=split;read(BIG,$_,$2,$1)' -- -BIG=$2 index.dat > output.dat` with the same error . Thanks	[reply] [d/l]
Re^9: Offset Reading - two files by BrowserUk (Patriarch) on Dec 14, 2012 at 16:47 UTC
You are still trying to use the readonly variables $1 & $2, hence the error message. I suggest that you learn simple Perl, before you try to do complicated things with it. If you do not have enough time to learn, employ someone to do it for you. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. RIP Neil Armstrong	[reply]
Re^10: Offset Reading - two files by gio001 (Acolyte) on Dec 14, 2012 at 17:32 UTC
Thanks so much. I got this to work. `<p>perl -sple 'BEGIN{open BIG};($offse,$recl)=split;seek(BIG,$offse,0);read(BIG,$_,$recl)' -- -BIG=datain index.dat >out </p>` Thanks for the support. I promise I will put more time in learning the basics before bothering you again. Bye	[reply] [d/l]
Re^8: Offset Reading - two files by gio001 (Acolyte) on Dec 14, 2012 at 17:22 UTC
Thanks so much. I got this to work. `<p>perl -sple 'BEGIN{open BIG};($offse,$recl)=split;seek(BIG,$offse,0);read(BIG,$_,$recl)' -- -BIG=datain index.dat >out </p>` Thanks for the support. I promise I will put more time in learning the basics before bothering you again. Bye	[reply] [d/l]