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Practical Programming in Tcl & Tk, Third Edition
By Brent B. Welch

Table of Contents
Chapter 5.  Tcl Lists


Searching Lists: lsearch

lsearch returns the index of a value in the list, or -1 if it is not present. lsearch supports pattern matching in its search. Glob-style pattern matching is the default, and this can be disabled with the -exact flag. The semantics of glob pattern matching is described in Chapter 4. The -regexp option lets you specify the list value with a regular expression. Regular expressions are described in Chapter 11. In the following example, the glob pattern l* matches the value list.

lsearch {here is a list}l*
=> 3

Example 5-6 uses lreplace and lsearch to delete a list element by value. The value is found with lsearch. The value is removed with an lreplace that does not specify any replacement list elements:

Example 5-6 Deleting a list element by value.
proc ldelete {list value } {
   set ix [lsearch -exact $list $value]
   if {$ix >= 0} {
      return [lreplace $list $ix $ix]
   } else {
      return $list
   }
}

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