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Jagg
Halfop
Joined: 24 Jan 2004
Posts: 53
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 Posted: Sat Jan 24, 2004 11:43 am Post subject: list specific chapter from a href tag? |
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Hi,
I have a html-file. In the source code there are many a href-tags which looks like
<a href = "http://www.url.com/e?t=WORD" target="_blank">WORD</a>
<a href = "http://www.url.com/e?t=WORD2" target="_blank">WORD2</a>
and so on....
How can I list all blue WORD* ?
Thanks |
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user
Joined: 18 Mar 2003
Posts: 1452
Location: Norway
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| Posted: Sat Jan 24, 2004 9:34 pm Post subject: Re: list specific chapter from a href tag? |
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Try this: | Code: | foreach {word word} [regexp -all -inline {"http://www.url.com/e\?t=([^"]+)"} $html] {
lappend words $word
} |
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Jagg
Halfop
Joined: 24 Jan 2004
Posts: 53
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| Posted: Sun Jan 25, 2004 1:19 pm Post subject: Re: list specific chapter from a href tag? |
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THANKS A LOT!!!!!
I get now a list from all WORD like:
| Quote: | | WORD WORD2 WORD3 and so on... |
How can I write a comma between these words? |
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strikelight
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Joined: 07 Oct 2002
Posts: 708
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| Posted: Sun Jan 25, 2004 5:35 pm Post subject: |
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By converting it to a string with "join" and telling it what to join with, ie. a comma:
| Code: |
set text [join $yourlist ", "]
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Jagg
Halfop
Joined: 24 Jan 2004
Posts: 53
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| Posted: Wed Jan 28, 2004 9:17 am Post subject: |
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Ok, it works perfect now..... BUT there is a problem 
The server allows only ~445 characters per line! Sometimes the output of the above script is more than 445 characters so it stops after this amount of ch. 
With which command I can say/split the output in two, three lines when var $a is more than 445 characters? |
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user
Joined: 18 Mar 2003
Posts: 1452
Location: Norway
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| Posted: Wed Jan 28, 2004 2:30 pm Post subject: |
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| Jagg wrote: | | With which command I can say/split the output in two, three lines when var $a is more than 445 characters? |
There's no single command to do that 
This is a pretty straight forward word wrapper. the optional third value can be used to split on a different char than space (only one char..sorry ) It returns a list of "lines" that you can do whatever you like with 
| Code: |
proc wordwrap {str {len 70} {splitChr { }}} {
set out [set cur {}]; set i 0
foreach word [split [set str][unset str] $splitChr] {
if {[incr i [string len $word]]>$len} {
lappend out [join $cur $splitChr]
set cur [list $word]
set i [string len $word]
} {
lappend cur $word
}
incr i
}
lappend out [join $cur $splitChr]
}
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ps: it won't split words even if they're longer than the max length. feature or bug? you decide
pps: it will return a list with one empty element if you feed it an empty string
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strikelight
Owner
Joined: 07 Oct 2002
Posts: 708
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| Posted: Wed Jan 28, 2004 7:42 pm Post subject: |
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| user wrote: | | Jagg wrote: | | With which command I can say/split the output in two, three lines when var $a is more than 445 characters? |
There's no single command to do that
This is a pretty straight forward word wrapper. the optional third value can be used to split on a different char than space (only one char..sorry ) It returns a list of "lines" that you can do whatever you like with
| Code: |
proc wordwrap {str {len 70} {splitChr { }}} {
set out [set cur {}]; set i 0
foreach word [split [set str][unset str] $splitChr] {
if {[incr i [string len $word]]>$len} {
lappend out [join $cur $splitChr]
set cur [list $word]
set i [string len $word]
} {
lappend cur $word
}
incr i
}
lappend out [join $cur $splitChr]
}
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ps: it won't split words even if they're longer than the max length. feature or bug? you decide
pps: it will return a list with one empty element if you feed it an empty string |
What's the point of unsetting the local variable str? Sure you free up a little bit of memory, but with the command substitution you are adding cpu time... The local variable will be destroyed once the procedure has exited anyways, so for the little time it does spend inside the proc, plus the slight cpu overhead, there's no advantage to unsetting it. |
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user
Joined: 18 Mar 2003
Posts: 1452
Location: Norway
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| Posted: Wed Jan 28, 2004 7:55 pm Post subject: |
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| strikelight wrote: | | What's the point of unsetting the local variable str? Sure you free up a little bit of memory, but with the command substitution you are adding cpu time... The local variable will be destroyed once the procedure has exited anyways, so for the little time it does spend inside the proc, plus the slight cpu overhead, there's no advantage to unsetting it. |
The point is to not have two copies of the entire input stored in memory at any point. In my opinion, saving ~50% memory (for large amounts of data) outweights the disadvantage of the tiny cpu usage added by the unset.
But it probably doesn't matter for what these folks will use it for anyway...and to be perfectly honest I did it to make the boring code have a slightly interesting part for us to talk about right now
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strikelight
Owner
Joined: 07 Oct 2002
Posts: 708
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| Posted: Wed Jan 28, 2004 8:12 pm Post subject: |
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| user wrote: | | strikelight wrote: | | What's the point of unsetting the local variable str? Sure you free up a little bit of memory, but with the command substitution you are adding cpu time... The local variable will be destroyed once the procedure has exited anyways, so for the little time it does spend inside the proc, plus the slight cpu overhead, there's no advantage to unsetting it. |
The point is to not have two copies of the entire input stored in memory at any point. In my opinion, saving ~50% memory (for large amounts of data) outweights the disadvantage of the tiny cpu usage added by the unset.
But it probably doesn't matter for what these folks will use it for anyway...and to be perfectly honest I did it to make the boring code have a slightly interesting part for us to talk about right now |
Nothing wrong with us having a discussion about it though 
| Code: |
% proc a {mylist} {set i 0; foreach word $mylist {incr i}}
% proc b {mylist} {set i 0; foreach word [set mylist][unset mylist] {incr i}}
% time {a $mylist} 1000
26 microseconds per iteration
% time {b $mylist} 1000
81 microseconds per iteration
% time {a $mylist} 1000
36 microseconds per iteration
% time {b $mylist} 1000
91 microseconds per iteration
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so while you are correct in stating that you save ~50% in memory,
you are also adding ~200% to ~300% in cpu time |
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user
Joined: 18 Mar 2003
Posts: 1452
Location: Norway
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| Posted: Wed Jan 28, 2004 8:27 pm Post subject: |
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| strikelight wrote: | | Code: |
% proc a {mylist} {set i 0; foreach word $mylist {incr i}}
% proc b {mylist} {set i 0; foreach word [set mylist][unset mylist] {incr i} |
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Your test is not fair, as 'unset' returns an empty STRING, making the list before it become a string that has to be translated back to a list by foreach. (oh, the wonderfull internals of tcl ;P)
Try this instead and you'll see the unset adds very little to the total cpu usage
| Code: |
proc a it {set i 0; foreach word [split $it] {incr i}; set i}
proc b it {set i 0; foreach word [split [set it][unset it]] {incr i}; set i}
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strikelight
Owner
Joined: 07 Oct 2002
Posts: 708
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| Posted: Wed Jan 28, 2004 8:36 pm Post subject: |
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| user wrote: | | strikelight wrote: | | Code: |
% proc a {mylist} {set i 0; foreach word $mylist {incr i}}
% proc b {mylist} {set i 0; foreach word [set mylist][unset mylist] {incr i} |
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Your test is not fair, as 'unset' returns an empty STRING, making the list before it become a string that has to be translated back to a list by foreach
try this instead and you'll see the unset adds very little to the total cpu usage
| Code: |
proc a it {set i 0; foreach word [split $it] {incr i}; set i}
proc b it {set i 0; foreach word [split [set it][unset it]] {incr i}; set i}
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You are correct...
| Code: |
% proc b {mylist} {set i 0; foreach word [split [set mylist][unset mylist]] {incr i}}
% proc a {mylist} {set i 0; foreach word [split $mylist] {incr i}}
% time {a $mylist} 1000
126 microseconds per iteration
% time {b $mylist} 1000
178 microseconds per iteration
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Still ~50% cpu increase though. |
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user
Joined: 18 Mar 2003
Posts: 1452
Location: Norway
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| Posted: Wed Jan 28, 2004 8:38 pm Post subject: |
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How long is the string you're testing it with? To be on-topic it should be > 445 bytes
Oh..and what's the point of 'i'?
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strikelight
Owner
Joined: 07 Oct 2002
Posts: 708
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| Posted: Wed Jan 28, 2004 8:48 pm Post subject: |
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| user wrote: | How long is the string you're testing it with? To be on-topic it should be > 445 bytes
Oh..and what's the point of 'i'? |
It was 271 bytes....
Now it is:
| Code: |
% string bytelength $mylist
547
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'i' just gives the procs something to do to simulate that they are doing something meaningful ;x
| Code: |
% time {a $mylist} 1000
305 microseconds per iteration
% time {b $mylist} 1000
391 microseconds per iteration
% time {a $mylist} 1000
277 microseconds per iteration
% time {b $mylist} 1000
336 microseconds per iteration
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So it's STILL ~20% - ~30% increase.
heh. I guess we can agree, like most things, it's a trade off of memory vs performance. |
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user
Joined: 18 Mar 2003
Posts: 1452
Location: Norway
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| Posted: Thu Jan 29, 2004 6:35 am Post subject: |
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| strikelight wrote: | | heh. I guess we can agree, like most things, it's a trade off of memory vs performance. |
Yeah...it seems most tcl versions are faster at setting the value to an empty string instead of deleting the entire variable, so I guess I should make it | Code: | | foreach word [split [set str][set str ""] $splitChr] {...} |
And to make it even faster I could replace all variable substitutions with [set ..], but then the code will be much harder to read.
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strikelight
Owner
Joined: 07 Oct 2002
Posts: 708
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| Posted: Thu Jan 29, 2004 10:20 pm Post subject: |
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| user wrote: | | strikelight wrote: | | heh. I guess we can agree, like most things, it's a trade off of memory vs performance. |
Yeah...it seems most tcl versions are faster at setting the value to an empty string instead of deleting the entire variable, so I guess I should make it | Code: | | foreach word [split [set str][set str ""] $splitChr] {...} |
And to make it even faster I could replace all variable substitutions with [set ..], but then the code will be much harder to read. |
From my tests, variable substitutions seem to be on exact par with command substitutions. (except for those command substitutions which also involve variable substitutions at the same time, of course). |
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