lassign(n) [mojave man page]

lassign(n)						       Tcl Built-In Commands							lassign(n)

__________________________________________________________________________________________________________________________________________________

NAME

       lassign - Assign list elements to variables

SYNOPSIS

       lassign list varName ?varName ...?
_________________________________________________________________

DESCRIPTION

       This command treats the value list as a list and assigns successive elements from that list to the variables given by the varName arguments
       in order.  If there are more variable names than list elements, the remaining variables are set to the empty string.   If  there  are  more
       list elements than variables, a list of unassigned elements is returned.

EXAMPLES

       An illustration of how multiple assignment works, and what happens when there are either too few or too many elements.
	      lassign {a b c} x y z	  ;# Empty return
	      puts $x			  ;# Prints "a"
	      puts $y			  ;# Prints "b"
	      puts $z			  ;# Prints "c"

	      lassign {d e} x y z	  ;# Empty return
	      puts $x			  ;# Prints "d"
	      puts $y			  ;# Prints "e"
	      puts $z			  ;# Prints ""

	      lassign {f g h i} x y	  ;# Returns "h i"
	      puts $x			  ;# Prints "f"
	      puts $y			  ;# Prints "g"
       The lassign command has other uses.  It can be used to create the analogue of the "shift" command in many shell languages like this:
	      set ::argv [lassign $::argv argumentToReadOff]

SEE ALSO

       lindex(n), list(n), lset(n), set(n)

KEYWORDS

       assign, element, list, multiple, set, variable

Tcl									8.5								lassign(n)

split(n)						       Tcl Built-In Commands							  split(n)

__________________________________________________________________________________________________________________________________________________

NAME

       split - Split a string into a proper Tcl list

SYNOPSIS

       split string ?splitChars?
_________________________________________________________________

DESCRIPTION

       Returns a list created by splitting string at each character that is in the splitChars argument.  Each element of the result list will con-
       sist of the characters from string that lie between instances of the characters in splitChars.  Empty list elements will  be  generated	if
       string contains adjacent characters in splitChars, or if the first or last character of string is in splitChars.  If splitChars is an empty
       string then each character of string becomes a separate element of the result list.  SplitChars defaults to the standard white-space  char-
       acters.

EXAMPLES

       Divide up a USENET group name into its hierarchical components:
	      split "comp.lang.tcl.announce" .
		    -> comp lang tcl announce

       See how the split command splits on every character in splitChars, which can result in information loss if you are not careful:
	      split "alpha beta gamma" "temp"
		    -> al {ha b} {} {a ga} {} a

       Extract the list words from a string that is not a well-formed list:
	      split "Example with {unbalanced brace character"
		    -> Example with {unbalanced brace character

       Split a string into its constituent characters
	      split "Hello world" {}
		    -> H e l l o { } w o r l d

   PARSING RECORD-ORIENTED FILES
       Parse a Unix /etc/passwd file, which consists of one entry per line, with each line consisting of a colon-separated list of fields:
	      ## Read the file
	      set fid [open /etc/passwd]
	      set content [read $fid]
	      close $fid

	      ## Split into records on newlines
	      set records [split $content "
"]

	      ## Iterate over the records
	      foreach rec $records {

		 ## Split into fields on colons
		 set fields [split $rec ":"]

		 ## Assign fields to variables and print some out...
		 lassign $fields 
		       userName password uid grp longName homeDir shell
		 puts "$longName uses [file tail $shell] for a login shell"
	      }

SEE ALSO

       join(n), list(n), string(n)

KEYWORDS

       list, split, string

Tcl																	  split(n)