查看“变量转换”的源代码

==浮点数转成整数==
*round:四舍五入 
 IDL>print,round(5.1),round(5.9)
 IDL> 5, 6
*ceil:向上进
 IDL>print,ceil(5.1),ceil(5.9)
 IDL> 6, 6
*floor:截取整数
 IDL>print,floor(5.1),floor(5.9)
 IDL> 5, 5

*结果是long型的整数，要转换更大的数，加上/L64
*[[astro_lib]]中的nint程序，可以代替round，而且
:(1) if no absolute value exceeds 32767, then the array is returned as a type INTEGER instead of LONG
:(2) NINT will work on strings, e.g. print,nint(['3.4','-0.9']) will give [3,-1], whereas ROUND() gives an error message

==消除变量==
*temporary(var)