TCL lsearch -regexp

grob115 · 11-20-2009, 09:19 AM

Am trying to test whether any one of the items in a list contains the word "hello" but failed. Any idea why?

Here is the actual code:
if { [lsearch -regexp $line *hello*] >= 0 } {
}

This is what I got:
Invocation of "<procname>" failed with error "couldn't compile regular expression pattern: ?+* follows nothing"

In fact I want to do the following. Basically there are a number of digits preceding "hello", followed by one digit.
if { [lsearch -regexp $line [0-9]+hello[0-9]] >= 0 } {
}

timmeke · 11-20-2009, 12:09 PM

1/ Are you sure $line is a list?
2/ Which version of Tcl are you using 8.4? 8.5?
3/ *hello* is not a valid regexp. Check out http://www.tcl.tk/man/tcl8.4/TclCmd/re_syntax.htm: * has special meaning.
If you mean "any number (incl none at all) of random characters", then use .*
If you mean "any non-zero number of random chars", then use .+
4/ If you intend to use the 2nd pattern with the digits, why try the first one anyhow?

The error clearly marks your regular expression as the culprit.

grob115 · 11-21-2009, 10:30 AM

Ah I see. Actually this is the original form I tried but still doesn't work. I want to match a pattern such as 1234hello1 or 2345hello2, etc. And yes $line is a list.

Any idea why [0-9]+hello[0-9] wouldn't work?

if { [lsearch -regexp $line [0-9]+hello[0-9]] >= 0 } {
}

Quote:

Originally Posted by timmeke

1/ Are you sure $line is a list?
2/ Which version of Tcl are you using 8.4? 8.5?
3/ *hello* is not a valid regexp. Check out http://www.tcl.tk/man/tcl8.4/TclCmd/re_syntax.htm: * has special meaning.
If you mean "any number (incl none at all) of random characters", then use .*
If you mean "any non-zero number of random chars", then use .+
4/ If you intend to use the 2nd pattern with the digits, why try the first one anyhow?

The error clearly marks your regular expression as the culprit.

jlinkels · 11-22-2009, 08:31 PM

Quote:

Originally Posted by grob115

Any idea why [0-9]+hello[0-9] wouldn't work?

if { [lsearch -regexp $line \[0-9\]+hello\[0-9\]] >= 0 } {
}

For me it works now

jlinkels