See if a list contains a particular element
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. If not, the command returns -1.
The mode argument indicates how the elements of the list are to be matched against pattern and it must have one of the following values:
The list element must contain exactly the same string as pattern.
Pattern is a glob-style pattern which is matched against each list element using the same rules as the string match command.
Pattern is treated as a regular expression and matched against each list element using the same rules as the regexp command.
list, match, pattern, regular expression, search, string