I am trying to understand the notion of density in the context of Banach spaces. The density of a topological space is the least cardinality of a dense subset. Thus, a separable Banach space has density $\omega$.
What is the density of $l_\infty$? What about density of $C([0,1])$? Can one build a Banach space of arbitrary density? Is there a good reference for this topic?