Transformations
Methods for transforming arrays and for generating new arrays. 用于转换数组的方法
- d3.flatGroup - group an iterable into a flat array.两重或多重group,和groups类似只是传参方式不同
- d3.flatRollup - reduce an iterable into a flat array.两重或多重rollup,和rollups类似只是传参方式不同
- d3.group - group an iterable into a nested Map. group by key将元素字段名作为index 聚合元素
- d3.groups - group an iterable into a nested array. 多重group方法
- d3.groupSort - sort keys according to grouped values. 根据聚合计算后值排序元素，并能放回去重后排序的元素指定字段数组
- d3.index - index an iterable into a nested Map.将元素字段值作为index 聚合元素
- d3.indexes - index an iterable into a nested array.多重index方法
- d3.rollup - reduce an iterable into a nested Map.分组并根据组员值进行计算，并返回计算后的分组结果
- d3.rollups - reduce an iterable into a nested array.多重rollu方法
- d3.count - count valid number values in an iterable.根据元素字段字段值进行计数
- d3.cross - compute the Cartesian product of two iterables.求笛卡尔积
- d3.merge - merge multiple iterables into one array.合并
- d3.pairs - create an array of adjacent pairs of elements.用数组元素两两重组一个数组
- d3.permute - reorder an iterable of elements according to an iterable of indexes.用指定排序数组对原数组进行重排
- d3.shuffle - randomize the order of an iterable.随机重排
- d3.shuffler - randomize the order of an iterable. 使用指定seed生成随机重排函数
- d3.ticks - generate representative values from a numeric interval.生成刻度数组
- d3.tickIncrement - generate representative values from a numeric interval.获得生成刻度 步增值
- d3.tickStep - generate representative values from a numeric interval.获得生成刻度 总步数（刻度）
- d3.nice - extend an interval to align with ticks. 获得一个修正过的生成总步数（保证与刻度对其）
- d3.range - generate a range of numeric values. like python range获得范围值数组 默认increment为1的ticks方法
- d3.transpose - transpose an array of arrays. zip压缩的另外一种形式（参数传递方式不同）
- d3.zip - transpose a variable number of arrays.将两个数组压缩成一个
