Swap you for one of these

Around half past twelve there was a great clattering outside in the corridor and a smiling, dim-pled woman slid back their door and said, "Anything off the cart, dears?"
Harry, who hadn't had any breakfast, leapt to his feet, but Ron's ears went pink again and he muttered that he'd brought sandwiches. Harry went out into the corridor.
He had never had any money for candy with the Dursleys, and now that he had pockets rattling with gold and silver he was ready to buy as many Mars Bars as he could carry -- but the woman didn't have Mars Bars. What she did have were Bettie Bott's Every Flavor Beans, Drooble's Best Blowing Gum, Chocolate Frogs. Pumpkin Pasties, Cauldron Cakes, Licorice Wands, and a number of other strange things Harry had never seen in his life. Not wanting to miss anything, he got some of everything and paid the woman eleven silver Sickles and seven bronze Knuts.
Ron stared as Harry brought it all back in to the compartment and tipped it onto an empty seat.
"Hungry, are you?"
"Starving," said Harry, taking a large bite out of a pumpkin pasty.
Ron had taken out a lumpy package and unwrapped it. There were four sandwiches inside. He pulled one of them apart and said, "She always forgets I don't like corned beef."
"Swap you for one of these," said Harry, holding up a pasty. "Go on --"
"You don't want this, it's all dry," said Ron. "She hasn't got much time," he added quickly, "you know, with five of us." (Harry Potter and the Sorcerer's Stone)

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I’m curious what it would be, had there been some words before swap. I guess ‘I’d like’ could be one of them, but I’m not so sure. What examples can there be?