doesn't mean a string bean

[frindle2]

Hello. I'm wondering what 'a string bean' means in the context below.
Does it mean same as 'spill the beans' or something?

(The speaker is a sheriff who is chasing outlaws. The speaker and other sheriff are about to jump on the outlaws in the cave.)
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"They'll know we're coming if they got ahold of the marshal.
The fact that the marshal's horse isn't here with these others doesn't mean a string bean.
If the horse was lame, they would've shot it and dumped it into the creek.
Could've done the same to the marshal, too , for all we know."

Source: Pony by R. J. Palacio

 

[White Hat]

I think it means that the fact that the horse isn't there means nothing.

 

[5jj]

Hello. I'm wondering what 'a string bean' means in the context below.

If you want to know what it means, ask us; don't tell us you're wondering.

It doesn't mean a string bean means It doesn't mean a thing.
Crossposted.