条件字符串插值

下面的语法有什么问题?我想分配 x 到 {diff} short of 如果 diff > 0 否则应为空字符串。

diff = 1
x = f"{diff 'short of' if diff > 0 else ''}"

编辑: 根据评论,正确的方法是:

x = f"{diff} short of" if diff > 0 else ""

但是,我也需要 X 在另一个字符串插值中,例如

y = f"That's {x} your best"

现在问题是如果 X 是空的,有一个 额外的 空间在 y ,即y= "That's your best" 而不是 "That's your best" . 字符串插值是否自动添加空格?