const a = [{ num: '张无忌', price: 123 },{ num: '周芷若', price: 666 },]console.log(a.map((item) => item.num))console.log('map方法a,a是不变的，要有人接受他才行')console.log(a)let b = []b = a.map((item) => item.num)console.log(b)

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