Question

我正在尝试使用dattime X timedelta

绘制图表

def graph_entre_mamadas(tempo_entre_mamadas):
    import matplotlib.pyplot as plt
    import matplotlib
    eixo_x = [i[0] for i in tempo_entre_mamadas]
    eixo_y = [i[1] for i in tempo_entre_mamadas]
    #print eixo_x
    #print eixo_y

    plt.plot(eixo_x, eixo_y, 'ro')
    plt.gcf().autofmt_xdate()
    plt.show()

我的变量eixo_x是datetime.datetime的列表，而eixo_y变量是datetime.timedelta的列表。

当我执行此方法时，我收到此错误：

  graph_entre_mamadas(tempo_entre_mamadas_v)
  File "consome_mama.py", line 111, in graph_entre_mamadas
    plt.plot(eixo_x, eixo_y, 'ro')
  File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 2832, in plot
    ret = ax.plot(*args, **kwargs)
  File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 3997, in plot
    self.add_line(line)
  File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 1507, in add_line
    self._update_line_limits(line)
  File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 1516, in _update_line_limits
    path = line.get_path()
  File "/usr/lib/pymodules/python2.7/matplotlib/lines.py", line 677, in get_path
    self.recache()
  File "/usr/lib/pymodules/python2.7/matplotlib/lines.py", line 410, in recache
    y = np.asarray(yconv, np.float_)
  File "/usr/lib/python2.7/dist-packages/numpy/core/numeric.py", line 320, in asarray
    return array(a, dtype, copy=False, order=order)
TypeError: float() argument must be a string or a number



eixo_x : [datetime.datetime(2014, 6, 27, 9, 21, 28), datetime.datetime(2014, 6, 27, 10, 50, 28), datetime.datetime(2014, 6, 27, 13, 26, 28), datetime.datetime(2014, 6, 27, 15, 36, 28), datetime.datetime(2014, 6, 27, 16, 36, 28), datetime.datetime(2014, 6, 27, 17, 23, 28), datetime.datetime(2014, 6, 27, 20, 40, 28), datetime.datetime(2014, 6, 27, 21, 20, 28), datetime.datetime(2014, 6, 27, 22, 11, 28), datetime.datetime(2014, 6, 28, 2, 42, 28)]
eixo_y : [datetime.timedelta(0, 9000), datetime.timedelta(0, 4440), datetime.timedelta(0, 8100), datetime.timedelta(0, 7140), datetime.timedelta(0, 1800), datetime.timedelta(0, 1920), datetime.timedelta(0, 10920), datetime.timedelta(0, 1320), datetime.timedelta(0, 1920), datetime.timedelta(0, 13740)]

我该怎么做？

Answer 1

Matplotlib不提供转换timedelta的简单方法。

但是，您可以使用matplotlib.dates.date2num轻松转换matplotlib浮点表示中的日期。

因此，一个有效的解决方案是使用开始时间加上delta来创建日期，然后使用date2num转换它们，最后在转换它们时将两个日期区分开来。

以下是一个例子：

import matplotlib
import datetime

x0 = datetime.datetime(2014, 6, 27, 9, 21, 28)
duration = datetime.timedelta(hours=1)
converted_starting_time = matplotlib.dates.date2num(x0)
converted_finish_time = matplotlib.dates.date2num(x0 + duration)
converted_delta = converted_finish_time - converted_starting_time

如何使用matplotlib用timedelta绘制图形

1 个答案: