R, function () returns an integer (0)

Question

I like to extract the index number from the list. The which () function returns an integer (0), and I don't know why. I created a list containing the following vector

[[5]]$bar

[1] -1.35 -1.34 -1.33 ,....,
[121] -0.15 -0.14 -0.13 -0.12 -0.11 -0.10 -0.09 -0.08 -0.07 -0.06 -0.05

which I retrieve with:

b <- foo[[5]]$bar

Now I want to request an index number from -1.35 (for example). I used the command: which (b == -1.35)and returns an integer (0) instead of [1].

If I create a similar vector with <- c (x, ..., - 1.35), which function will return the index number correct. Both a and b are numeric vectors with elements of type double, where is the difference between them and how can I extract the index number from the list?

Thank you for your help!