In Maya, when using the setAttr() command, we can use float and double as a variable type. What is the difference? The example in the documentation is the same one.
-type float3
Array of three floats
Value Syntax float float float
Value Meaning value1 value2 value3
Mel Example setAttr node.float3Attr -type float3 1.1 2.2 3.3;
Python Example cmds.setAttr('node.float3Attr',1.1,2.2,3.3,type='float3')
-type double3
Array of three doubles
Value Syntax double double double
Value Meaning value1 value2 value3
Mel Example setAttr node.double3Attr -type double3 1.1 2.2 3.3;
Python Example cmds.setAttr('node.double3Attr',1.1,2.2,3.3,type='double3')
http://download.autodesk.com/global/docs/maya2014/en_us/CommandsPython/index.html
Thank you!