How can I separate csh array elements with something other than a space?

In a csh script I'm working on I need to have array elements containing spaces, so I need to separate those elements with something other than a space, like a comma. For example, I would like to initialize my array with something like:

set the_array=('Element 1','Element 2','Element 3','Element 4')

Note: I'm well aware of how undesirable it is to work in csh. However, for this project I have no choice ... and yes, I've tried to convince the powers that be that this should be changed, but there is already a large code base that would have to be re-written, so that's been rejected.

Solution

There are two ways to initialize an array of strings (that have white spaces in them) in CSH:

The first way, using commas, uses the brace syntax, or the "glob pattern":

% set the_array = {'Element 1','Element 2','Element 3','Element 4'}
% echo $the_array[1]
Element 1

The second way, without commas, uses parentheses:

% set the_array = ('Element 1' 'Element 2' 'Element 3' 'Element 4')
% echo $the_array[1]
Element 1

This way also allows you to create an array over multiple lines:

% set the_array = ('Element 1' \
? 'Element 2')
% echo $the_array[1]
Element 1
% echo $the_array[2]
Element 2

To iterate through the_array, you can't simply access each element in a foreach as the following:

% foreach i ( $the_array )
foreach? echo $i
foreach? end
Element
1
Element
2
Element
3
Element
4

You need to loop from 1 to N, where N is the length of the array, using seq, shown below:

% foreach i ( `seq $the_array` )
foreach? echo $the_array[$i]
foreach? end
Element 1
Element 2
Element 3
Element 4

Note that CSH uses 1-based indexing.

Unfortunately, as you found out, using parentheses with commas will produce the following:

% set the_array = ('Element 1','Element 2','Element 3','Element 4')
% echo $the_array[1]
Element 1,Element 2,Element 3,Element 4

Sources