bar()函数不能直接分类,它的横坐标仍然是标量刻度,要用xticks来映射分类.
matplotlib.pyplot.bar(left, height, width=0.8, bottom=None, hold=None, data=None, **kwargs)
参数
left : sequence of scalarsheight : sequence of scalarswidth : scalar or array-like, optionalbottom : scalar or array-like, optionalcolor : scalar or array-like, optional(填充颜色)edgecolor : scalar or array-like, optional(边缘颜色)linewidth : scalar or array-like, optional(边缘宽度)tick_label : string or array-like, optional(刻度标签)xerr : scalar or array-like, optionalyerr : scalar or array-like, optionalecolor : scalar or array-like, optionalcapsize : scalar, optionalerror_kw : dict, optionalalign : {‘center’, ‘edge’}, optional(对齐方式)orientation : {‘vertical’, ‘horizontal’}, optional(方向)log : boolean, optional(log刻度)返回值
bars : matplotlib.container.BarContainer
