lsearchn
See if a list contains a particular element
Usage
lsearch ?options? list pattern
Overview
This command searches the elements of list to see if one of them matches pattern. If so, the command returns the index of the first matching element (unless the options -all or -inline are specified.) If not, the command returns -1. The option arguments indicates how the elements of the list are to be matched against pattern and must have one of the values below:
Matching style options
If all matching style options are omitted, the default matching style is -glob. If more than one matching style is specified, the last matching style given takes precedence.
-
-exact -
Pattern is a literal string that is compared for exact equality against each list element.
-
-glob -
Pattern is a glob-style pattern which is matched against each list element using the same rules as the string match command.
-
-regexp -
Pattern is treated as a regular expression and matched against each list element using the rules described in the
re_syntaxreference page.
-
-sorted -
The list elements are in sorted order. If this option is specified,
lsearchwill use a more efficient searching algorithm to search list. If no other options are specified, list is assumed to be sorted in increasing order, and to contain ASCII strings. This option is mutually exclusive with-globand-regexp, and is treated exactly like-exactwhen either-allor-notare specified.
General modifier options
These options may be given with all matching styles.
-
-all -
Changes the result to be the list of all matching indices (or all matching values if
-inlineis specified as well.) If indices are returned, the indices will be in numeric order. If values are returned, the order of the values will be the order of those values within the input list.
-
-inline -
The matching value is returned instead of its index (or an empty string if no value matches.) If
-allis also specified, then the result of the command is the list of all values that matched.
-
-not -
This negates the sense of the match, returning the index of the first non-matching value in the list.
-
-start index -
The list is searched starting at position index. The interpretation of the index value is the same as for the command string index, supporting simple index arithmetic and indices relative to the end of the list.
Contents description options
These options describe how to interpret the items in the list being searched. They are only meaningful when used with the -exact and -sorted options. If more than one is specified, the last one takes precedence. The default is -ascii.
-
-ascii -
The list elements are to be examined as Unicode strings (the name is for backward-compatibility reasons.)
-
-dictionary -
The list elements are to be compared using dictionary-style comparisons (see
lsortfor a fuller description). Note that this only makes a meaningful difference from the-asciioption when the-sortedoption is given, because values are only dictionary-equal when exactly equal.
-
-integer -
The list elements are to be compared as integers.
-
-nocase -
Causes comparisons to be handled in a case-insensitive manner. Has no effect if combined with the
-dictionary,-integer, or-realoptions.
-
-real -
The list elements are to be compared as floating-point values.
Sorted list options
These options (only meaningful with the -sorted option) specify how the list is sorted. If more than one is given, the last one takes precedence. The default option is -increasing.
-
-decreasing -
The list elements are sorted in decreasing order. This option is only meaningful when used with
-sorted.
-
-increasing -
The list elements are sorted in increasing order. This option is only meaningful when used with
-sorted.
Nested list options
These options are used to search lists of lists. They may be used with any other options.
-
-index indexList -
This option is designed for use when searching within nested lists. The indexList argument gives a path of indices (much as might be used with the
lindexorlsetcommands) within each element to allow the location of the term being matched against.
-
-subindices -
If this option is given, the index result from this command (or every index result when
-allis also specified) will be a complete path (suitable for use withlindexorlset) within the overall list to the term found. This option has no effect unless the -index is also specified, and is just a convenience short-cut.
Examples
Basic searching: lsearch {a b c d e} c
→ 2 lsearch -all {a b c a b c} c
→ 2 5
Using lsearch to filter lists: lsearch -inline {a20 b35 c47} b*
→ b35 lsearch -inline -not {a20 b35 c47} b*
→ a20 lsearch -all -inline -not {a20 b35 c47} b*
→ a20 c47 lsearch -all -not {a20 b35 c47} b*
→ 0 2
This can even do a removal operation: lsearch -all -inline -not -exact {a b c a d e a f g a} a
→ b c d e f g
Searching may start part-way through the list: lsearch -start 3 {a b c a b c} c
→ 5
It is also possible to search inside elements: lsearch -index 1 -all -inline {{a abc} {b bcd} {c cde}} *bc*
→ {a abc} {b bcd}
Keywords
list, match, pattern, regular expression, search, string
Releases
163 releases since Mac OS X 10.0; the text changed 3 times.
-all since Mac OS X 10.6;
-ascii since Mac OS X 10.6;
-decreasing since Mac OS X 10.6;
-dictionary since Mac OS X 10.6;
-increasing since Mac OS X 10.6;
-index since Mac OS X 10.6;
-inline since Mac OS X 10.6;
-integer since Mac OS X 10.6;
-nocase since Mac OS X 10.6;
-not since Mac OS X 10.6;
-real since Mac OS X 10.6;
-sorted since Mac OS X 10.6;
-start since Mac OS X 10.6;
-subindices since Mac OS X 10.6.