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Delete elements containing numeric entries from a list?

eft rsd
Posted 6 years ago

Hi, I have a large list of 1*2 lists that contain various dummy variables, something like 

list = {{a, b + c}, {u, y - h}, {d, g + h}, {d, 0}, {v, 0}}

I want to remove every element that has zero as the second entry, I have tried Select, DeleteCases andCases but none worked because Mathematica tried to equate variables to zero

How can I do that?

Thanks

eftsrd
POSTED BY: eft rsd
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I would try DeleteCases[list, {_, 0}].
POSTED BY: Gianluca Gorni

I would try DeleteCases[list, {_, 0}].
POSTED BY: Neil Singer
eft rsd
eft rsd
Posted 6 years ago

It worked! Thanks.
POSTED BY: eft rsd

My original post got corrupted and it repeated Gianluca's post.

I added to Gianluca's answer that there are many ways to do this and that your original attempts may have worked if you used === (SameQ) instead of ==. Mathematica does not know if g+h == 0 because g and h are not yet defined. However, Mathematica does know that g+h are not identical to 0. So if you are testing in Select, DeleteCases, Cases, etc. you usually need to use SameQ or UnSameQ and not Equals

Regards.

Neil
POSTED BY: Neil Singer
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