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-- Status: rewritten July 2018
-- Author: Lily Silverstein
doc///
Key
same
Headline
whether everything in a list is the same
Usage
same L
Inputs
L:
a list
Outputs
b:
a Boolean
Description
Example
same {1, 1, 1, 1}
same {1, 2, 1, 1}
Text
The comparison is done with "===", which is quick, but not always intuitive. Here is a
simple example of what can go wrong:
Example
R = QQ[x,y,z];
L = {gcd{x,y}, x/x, 1}
same L
Text
We can see the problem by asking {\tt Macaulay2} to display the class of each element of {\tt L}.
(Or use the function @TO uniform@, which returns whether or not the elements of a list
are all of the same class.)
Example
apply(L, class)
uniform L
Text
The first {\tt 1} is an element of the ring {\tt R}, the second {\tt 1} is an
element of the fraction field of {\tt R}, and the third {\tt 1} is an integer. Thus
{\tt Macaulay2} thinks of these three elements as being pairwise unequal, with respect
to the operator "===".
SeeAlso
commonest
number
set
uniform
unique
"lists and sequences"
///
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