How to get to the content of the data attribute of the input tag?

Question

XPath

Hello, tell me pliz
, here is the xpath trying to take the contents of the data-sell from the input

//input[@data-currency='USD']/@data-buy

with such a request gives

data-buy="74.19"
data-buy="74.19"
data-buy="74.19"

and I need first the first input and I don’t need only the content of the data attribute without the attribute itself, that is:

74.19

not completely

data-buy="74.19"

on the page this code

<input type="hidden" data-currency="USD" data-sell="78" data-buy="74.19">
<input type="hidden" data-currency="USD" data-sell="78" data-buy="74.19">
<input type="hidden" data-currency="USD" data-sell="78" data-buy="74.19">

Answer 1

First element, as it should be:
//input[@data-currency='USD'][1]
To return a value, I think it will do:
string(//input[@data-currency='USD'][1]/@data-buy)