Note that the indexvariable ( {i in TOY} ) comes before the :.
注意索引变量({i in TOY})都是在 : 之前出现的。
2
Try to use a differently named indexvariable for each set consistently; it's a good idea, especially when debugging.
我们可以试图为每个集合使用不同的命名索引变量;这是一个好主意,尤其是在进行调试时更为突出。
3
Note that the row and column order is the same as the element order in each set, and the indexvariable names are consistent between lines 12, 13, and 14.