String Concatenation

The addition operator is used to concatenate strings. For example, the command:

A = 'This is' + ' a concatenation example.' 
PRINT, A

results in the following output:

This is a concatenation example.

Strings can also be broken across code lines:

Print, "This is a multi-line " $ 
   + "string concatenation example."

results in the following output:

This is a multiline string concatenation example.

The following IDL statements build a scalar string containing a comma-separated list of the names found in the TREES string array:

; Create array of trees. 
trees = ['Beech', 'Birch', 'Mahogany', 'Maple', 'Oak', $ 
         'Pine', 'Walnut'] 
 
; Use REPLICATE to make an array with the correct number of commas  
; and add it to trees. 
names = trees + [REPLICATE(',', N_ELEMENTS(trees)-1), ''] 
 
; Show the resulting list. 
PRINT, names

Running the above statements results in the following output:

Beech, Birch, Mahogany, Maple, Oak, Pine, Walnut