d3.now() Returns the current time as defined by performance.now if available, and Date.now if not. The current time is updated at the start of a frame; it is thus consistent during the frame, and any timers scheduled during the same frame will be synchronized. If this method is called outside of a frame, such as in response to a user event, the current time is calculated and then fixed until the next frame, again ensuring consistent timing during event handling.

d3.nest() Creates a new nest operator. The set of keys is initially empty.

d3.namespaces The map of registered namespace prefixes. The initial value is: { svg: "http://www.w3.org/2000/svg", xhtml: "http://www.w3.org/1999/xhtml", xlink: "http://www.w3.org/1999/xlink", xml: "http://www.w3.org/XML/1998/namespace", xmlns: "http://www.w3.org/2000/xmlns/" } Additional prefixes may be assigned as needed to create elements or attributes in other namespaces.

d3.namespace(name) Qualifies the specified name, which may or may not have a namespace prefix. If the name contains a colon (:), the substring before the colon is interpreted as the namespace prefix, which must be registered in d3.namespaces. Returns an object space and local attributes describing the full namespace URL and the local name. For example: d3.namespace("svg:text"); // {space: "http://www.w3.org/2000/svg", local: "text"} If the name does not contain a colon, this function merely r

d3.mouse(container) Returns the x and y coordinates of the current event relative to the specified container. The container may be an HTML or SVG container element, such as a G element or an SVG element. The coordinates are returned as a two-element array of numbers [x, y].

d3.min(array[, accessor]) Returns the minimum value in the given array using natural order. If the array is empty, returns undefined. An optional accessor function may be specified, which is equivalent to calling array.map(accessor) before computing the minimum value. Unlike the built-in Math.min, this method ignores undefined, null and NaN values; this is useful for ignoring missing data. In addition, elements are compared using natural order rather than numeric order. For example, the minim

d3.merge(arrays) Merges the specified arrays into a single array. This method is similar to the built-in array concat method; the only difference is that it is more convenient when you have an array of arrays. d3.merge([[1], [2, 3]]); // returns [1, 2, 3]

d3.median(array[, accessor]) Returns the median of the given array of numbers using the R-7 method. If the array is empty, returns undefined. An optional accessor function may be specified, which is equivalent to calling array.map(accessor) before computing the median. This method ignores undefined and NaN values; this is useful for ignoring missing data.

d3.mean(array[, accessor]) Returns the mean of the given array of numbers. If the array is empty, returns undefined. An optional accessor function may be specified, which is equivalent to calling array.map(accessor) before computing the mean. This method ignores undefined and NaN values; this is useful for ignoring missing data.

d3.max(array[, accessor]) Returns the maximum value in the given array using natural order. If the array is empty, returns undefined. An optional accessor function may be specified, which is equivalent to calling array.map(accessor) before computing the maximum value. Unlike the built-in Math.max, this method ignores undefined values; this is useful for ignoring missing data. In addition, elements are compared using natural order rather than numeric order. For example, the maximum of ["20", "