golang数组引用例如b [1:4]引用元素1,2,3 [英] golang array referencing eg. b[1:4] references elements 1,2,3

问题描述

golang博客指出:

The golang blog states :

切片也可以通过切片"现有切片或数组来形成.切片是通过指定一个半开范围来完成的，其中两个索引之间用冒号分隔.例如，表达式b [1:4]创建包含b的元素1到3的切片(所得切片的索引将是0到2)."

"A slice can also be formed by "slicing" an existing slice or array. Slicing is done by specifying a half-open range with two indices separated by a colon. For example, the expression b[1:4] creates a slice including elements 1 through 3 of b (the indices of the resulting slice will be 0 through 2)."

有人可以向我解释上面的逻辑.IE.b [1:4]为什么不引用元素1到4?这是否与其他数组引用一致?

Can someone please explain to me the logic in the above. IE. Why doesn't b[1:4] reference elements 1 through 4? Is this consistent with other array referencing?

推荐答案

原因在切片.

对于字符串，数组或切片a，主要表达方式

For a string, array, or slice a, the primary expression

    a[low : high]

构造子字符串或切片.这索引表达式高低选择哪些元素出现在结果中.结果的索引从0开始并且长度等于高-低.

constructs a substring or slice. The index expressions low and high select which elements appear in the result. The result has indexes starting at 0 and length equal to high - low.

为方便起见，任何索引表达式可以省略.失踪低索引默认为零；失踪高索引默认为切片的操作数.

For convenience, any of the index expressions may be omitted. A missing low index defaults to zero; a missing high index defaults to the length of the sliced operand.

将切片的长度计算为高-低很容易而有效.

It's easy and efficient to calculate the length of the slice as high - low.

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