split

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 consist 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 characters.

Examples

Divide up a USENET group name into its hierarchical components:

split "comp.lang.tcl" .
      → comp lang tcl

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 "\n"]

## 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, list, string