"find" function doesn't work

12 次查看（过去 30 天）
Yuji Zhang
Yuji Zhang 2011-10-4
Hi~ I got a weird problem here. See the attached picture. "find" works for some values and doesn't for some others. It could a stupid question but can anybody help? Thanks a lot!
So the wavelength vector "lem" has some value but "find" can't find it.
The following is what happens in the command window. It can find the number value but can't find the variable x which equals that value.
>> x
x =
507.0350
>> jj = find(lem==x)
jj =
Empty matrix: 1-by-0
>> jj = find(lem==507.0350)
jj =
3408

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2011-10-4
find() works fine. Your array does not contain the value in x. If you were to try
lem(3408) - x
you would find that the result is non-zero.
See this FAQ
  6 个评论
显示 4更早的评论
Yuji Zhang
Yuji Zhang 2011-10-4
actually
jj = find(abs(10000000000*(lem-x))<1)
is a better way. because the error could be >0 or <0.
if it was -1e-14, floor(-1e-14)=-1
Walter Roberson
Walter Roberson 2011-10-4
Please examine the documentation for eps()

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Entering Commands 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by