April 22 (Reuters) - Star stock-picker Cathie Wood's Ark Invest this week snapped up shares of pandemic darlings including Roblox Corp, Roku Inc and Zoom Video Communications that have fallen out of favor this year. The asset manager shed more than half a million shares of Snap Inc SNAP.N this week, ahead of the company's earnings. The Snapchat owner slipped nearly 2% in premarket trading on Friday after warning inflation could hurt revenue growth in the current quarter.