If you are programming in Visual Basic, you can use the CBool function to convert the string representation of a number to a Boolean value. 0 is converted to false, and the string representation of any non-zero value is converted to true.
Nick is trying to figure out who Gatsby really is. Nick hears these rumors about gatsby, how he was a German spy, a murderer, etc.. Nick is disappointed with Gatsby because Gatsby has little too say. Nick wants Gatsby to tell him who he really is, what he does, where is he from. Unsurprisingly, Gatsby does not tell him, even though they talk a lot and hang out a lot. Nick is trying to figure out who Gatsby really is.
At the party Daisy seems to be very distasted with the events. This of course puts Gatsby down since in a way those parties had always been for Daisy. Gatsby had always thrown these parties in hope that maybe some day Daisy would waltz in. What Gatsby most wants is to impress Daisy, he wants her to want him.