error finding placement of specific number in a vector

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Candice Cooper 2021-5-25

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评论： Candice Cooper 2021-5-25

I have a single column vector named 'lon' of 8640 values. I'm trying to find which row has a certain value. I've tried using find(lon==120), but all it returns is an empty 0 x 1 double column vector. I've tried figuring this out online, but all I come across is the find function, which isn't working for me.

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Answer 1

DGM 2021-5-25

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编辑：DGM 2021-5-25

在 MATLAB Online 中打开

Does the vector contain 120?

Does the vector contain exactly 120?

If it's floating point, the answer might not be what you think it is.

A = linspace(0,10,19).'

A = 19×1

0 0.5556 1.1111 1.6667 2.2222 2.7778 3.3333 3.8889 4.4444 5.0000

find(A == 3.3333)

ans = 0×1 empty double column vector

find(abs(A-3.3333)<1E-3)

ans = 7

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Candice Cooper 2021-5-25

thank you!

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Answer 2

Sulaymon Eshkabilov 2021-5-25

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Hi,

Your data might be in a floating point format and if that is the case, then you need to be careful with logical indexing. If this is the case, you may need to use round up, select how many correct decimal digits to consider, and so forth. Moreover, inftead of find(Ion==120), you can use IND = (Ion==120) that shows you the indexes.

If you post your data, more specific answer will be provided.

Good luck.