Ana Maria Echeverri anamecheverri

Say your dataset is an array of numbers, and includes both positive and negative values. Use two scales to construct the bar chart: a quantitative scale (such as a [linear scale][1]) to compute the bar positions along the x-axis, and an [ordinal scale][2] with rangeBands to compute the bar positions along the y-axis.

For the quantitative scale, compute the data domain (the minimum and maximum value) using [d3.extent][3]:

var x = d3.scale.linear()
    .domain(d3.extent(data, function(d) { return d.value; }))
    .range([0, width]);

[Nicing][4] the scale will extend the extent slightly to the nearest round numbers. If you want the zero-value to be centered in the middle of the canvas, take the greater of the minimum and maximum value by magnitude, or simply hard-code the desired domain.

d3.legend

d3.legend is a quick hack to add a legend to a d3 chart. Simply add a g and .call(d3.legend). Any elements that have a title set in the "data-legend" attribute will be included when d3.legend is called. Each title will appear only once (even when multiple items define the same data-legend) as the process uses a set based on a existing names, not an array of all items.

Color

By default the color in the legend will try to match the fill attribute or the stroke attribute of the relevant items. Color can be explicitly defined by attribute "data-legend-color"

Order

The order of items in the legend will be sorted using the top of the bounding box for each included item. The order can be explicitly defined by attribute "data-legend-pos"

	#!/usr/bin/env python
	# encoding: utf-8

	import tweepy #https://github.com/tweepy/tweepy
	import csv

	#Twitter API credentials
	consumer_key = ""
	consumer_secret = ""
	access_key = ""