Lists 19-7
variable name (such as L1) or the actual list. For 
example, REVERSE({1,2,3}).
• If Decimal Mark in Modes is set to Comma, use 
periods to separate arguments. For example, 
CONCAT(L1.L2).
Common operators like +, –, ×, and / can take lists as 
arguments. If there are two arguments and both are lists, 
then the lists must have the same length, since the 
calculation pairs the elements. If there are two arguments 
and one is a real number, then the calculation pairs the 
number with each element of the list.
Example
5*{1,2,3} returns {5,10,15}.
Besides the common operators that can take numbers, 
matrices, or lists as arguments, there are commands that 
can only operate on lists.
CONCAT Concatenates two lists into a new list.
CONCAT(list1,list2)
Example
CONCAT({1,2,3},{4}) returns {1,2,3,4}.
ΔLIST Creates a new list composed of the first differences, that 
is, the differences between the sequential elements in 
list1. The new list has one fewer elements than list1. The 
first differences for {x
1
 x
2
 ... x
n
} are {x
2
–x
1
 ... x
n
–x
n–1
}.
ΔLIST(list1)
Example
In HOME, store {3,5,8,12,17,23} in L5 and find the first 
differences for the list.
 
{3,5,8,12,17,23 
}    
L 5
 L 
Select ΔLIST 
 L5 
hp40g+.book  Page 7  Friday, December 9, 2005  12:27 AM