Question

我之前写过的一个python脚本突然停止工作，我将matplotlib库从版本升级到0.99.1.1＆＃39;版本＆＃39; 1.2.x＆＃39;。

我正在使用python v 2.6.5

经过几个小时的调试，我终于找到了导致问题的线路。它们分为以下两行：

# Note: ax is an Axis type, phist is an iterable type
def function_no_longer_works(phist):
    # some code before ...
    ax.xaxis.set_major_locator(_MajorLocator(phist))
    ax.xaxis.set_major_formatter( FuncFormatter(_MajorFormatter(phist).format)
    # some code after ...



class _CanFit(object):
    def __init__(self, phist):
        self.phist = phist

    def weeks(self):
        if (self.phist[-1].date - self.phist[0].date).days > 5*30:
            # 5 months at most
            return False
        return True

    def months(self):
        if (self.phist[-1].date - self.phist[0].date).days > 3*365:
            # 3 years at most
            return False
        return True


class _MajorLocator(object):
    """calculates the positions of months or years on the y-axis

    These positions will be where the major ticks and labels for them are.
    If months can't fit, there are no major ticks, only minor ticks.

    """
    def __init__(self, phist):
        self.phist = phist

    def set_axis(self, axis): pass
    def view_limits(self, start, stop): pass

    def __call__(self):
        """returns an iterable of all the months or years on the y-axis"""
        can_fit = _CanFit(self.phist)
        major_ticks = []
        if can_fit.weeks():
            month = None
            # step through the price history list and find the index of every
            # point where the previous point has a different month
            for (i, p) in enumerate(self.phist):
                if month != p.date.month:
                    if month is not None:
                        major_ticks.append(i)
                    month = p.date.month
        elif can_fit.months():
            year = None
            # same as above, but for years.
            for (i, p) in enumerate(self.phist):
                if year != p.date.year:
                    if year is not None:
                        major_ticks.append(i)
                    year = p.date.year
        return major_ticks



class _MajorFormatter(object):
    """Formats the major ticks as years or months"""
    def __init__(self, phist):
        self.phist = phist

    def format(self, x, pos=None):
        can_fit = _CanFit(self.phist)
        if can_fit.weeks():
            # Jan Feb Mar etc
            return self.phist[x].date.strftime("%b") 
        if can_fit.months():
            # 90, 91, etc
            return self.phist[x].date.strftime("%y")

当我使用matplot lib v 1.2.x运行脚本时，这是堆栈跟踪：

/usr/local/lib/python2.6/dist-packages/matplotlib/axes.pyc in plot(self, *args, **kwargs)
   3851 
   3852 
-> 3853         self.autoscale_view(scalex=scalex, scaley=scaley)
   3854         return lines
   3855 

/usr/local/lib/python2.6/dist-packages/matplotlib/axes.pyc in autoscale_view(self, tight, scalex, scaley)
   1840                 x1 += delta
   1841             if not _tight:
-> 1842                 x0, x1 = xlocator.view_limits(x0, x1)
   1843             self.set_xbound(x0, x1)
   1844 

TypeError: 'NoneType' object is not iterable

过去几天我绞尽脑汁后，我的想法已经用完了。我们非常感谢您解决此问题的任何帮助。

Answer 1

您的问题是您没有在_MajorLocator.view_limits中返回任何内容。

预计会使用view_limits实现某种自动缩放方法。如果您不在乎，可以返回start和stop。

但是，您应该将matplotlib.ticker.AutoLocator（或其他定位器类）子类化，而不是从头开始。

否则，如果您想要自动缩放，则需要重新实现其view_limits方法。

从版本0.99.1.1移动到版本1.2.x时出现matplotlib轴格式错误

1 个答案: