Matplotlib和timestamp正在引发问题

为什么这不起作用？如何修复它？我试图绘制一个图形，其中x轴是时间轴，y值是csv文件中的第二列。我希望x打印标签的格式更易于阅读

testi.csv 睾丸2.py 这是我给出“python

回溯（最近一次呼叫最后一次）：
文件“”，第13行，在
savefig中的文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/pyplot.py”，第564行
返回图savefig（*args，**kwargs）
savefig中的文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/figure.py”，第1421行
self.canvas.print_图（*args，**kwargs）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/backend_base.py”，第2220行，如图所示
**kwargs）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/backends/backend_agg.py”，第505行，打印格式为png
图CAVASAGG.draw（自绘制）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/backends/backend_agg.py”，绘图中第451行
self.figure.draw（self.renderer）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/artist.py”，第54行，在draw_包装中
绘制（艺术家、渲染器、*args、**kwargs）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/figure.py”，绘图中的第1034行
func（*args）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/artist.py”，第54行，在draw_包装中
绘制（艺术家、渲染器、*args、**kwargs）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axes/_base.py”，绘图中的第2056行
a、 绘制（渲染器）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/artist.py”，第54行，在draw_包装中
绘制（艺术家、渲染器、*args、**kwargs）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axis.py”，绘图中的第1087行
勾号\u到\u绘制=自。\u更新\u勾号（渲染器）
文件“/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axis.py”，第945行，在更新中
tick_tups=[t代表self.iter_ticks（）中的t]
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axis.py”，第893行，在iter_中
对于i，枚举中的val（主要）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/dates.py”，第395行，在调用中__
dt=num2date（x，self.tz）
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/dates.py”，第329行，单位为num2date
从顺序lf（x，tz）返回
文件“/usr/local/lib/python2.7/dist packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/dates.py”，第218行，从
dt=datetime.datetime.fromordinal（ix）
ValueError:年份超出范围

您必须将时间戳转换为

datetime

对象

import numpy as np
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import matplotlib.dates as md
import datetime as dt

# create vectorized converter (can take list-like objects as arguments)
dateconv = np.vectorize(dt.datetime.fromtimestamp)

data = np.genfromtxt('testi.csv', delimiter=',', names=['t', 'btc', 'eur'])
plt.xkcd()

dates = dateconv(data['t']) # convert timestamps to datetime objects

plt.plot(dates, data['btc'], label='the data')
plt.xticks(dates, rotation=75, ha='right') # set ticks at plotted datetimes
ax=plt.gca()
xfmt = md.DateFormatter('%Y-%m-%d %H:%M:%S')
ax.xaxis.set_major_formatter(xfmt)

plt.tight_layout() # to make sure everything fits inside the figures boundaries

plt.savefig('testi2.png')

为了使为绘图设置的标签出现，必须在

plt.savefig（'testi2.png'）

之前调用

plt.legend（）

。使用

plt.legend（loc=2）

（将图例放在左上角）时，输出变为：

---

谢谢！太好了！：）实际上，它仍然给出了一些错误：Traceback（最后一次调用）：File“”，第9行，在文件“/usr/lib/python2.7/dist-packages/numpy/lib/function\u-base.py”中，第1818行，在init-nin中，ndefault=\u-get-nargs（pyfunc）文件“/usr/lib/python2.7/dist-packages/numpy/lib/function\u-base.py”，第1750行，在\u-get-nargs中无法确定%s“%的参数数（obj）)ValueError:无法确定任何想法的参数数量？您使用的是什么版本的numpy？您可以尝试更新您的numpy安装。我相信这是一个已修复的错误。另外，请参阅。或者，您可以定义一个函数，将numpy数组作为参数，转换数组中的元素，并返回t他转换了数组。>>>>导入numpy>>>>numpy。_u版本_u'1.6.1'我认为该错误在1.6.1版本后已修复。您应该更新numpy安装以避免此错误，或者您可以如上所述定义一个函数。

import numpy as np
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import matplotlib.dates as md
data = np.genfromtxt('testi.csv', delimiter=',', names=['t', 'btc', 'eur'])
plt.xkcd()
plt.plot(data['t'], data['btc'], label='the data')
plt.xticks(rotation=75)
ax=plt.gca()
xfmt = md.DateFormatter('%Y-%m-%d %H:%M:%S')
ax.xaxis.set_major_formatter(xfmt)
plt.savefig('testi2.png')

Traceback (most recent call last):
  File "<stdin>", line 13, in <module>
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/pyplot.py", line 564, in savefig
    return fig.savefig(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/figure.py", line 1421, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/backend_bases.py", line 2220, in print_figure
    **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/backends/backend_agg.py", line 505, in print_png
    FigureCanvasAgg.draw(self)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/backends/backend_agg.py", line 451, in draw
    self.figure.draw(self.renderer)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/artist.py", line 54, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/figure.py", line 1034, in draw
    func(*args)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/artist.py", line 54, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axes/_base.py", line 2056, in draw
    a.draw(renderer)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/artist.py", line 54, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axis.py", line 1087, in draw
    ticks_to_draw = self._update_ticks(renderer)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axis.py", line 945, in _update_ticks
    tick_tups = [t for t in self.iter_ticks()]
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/axis.py", line 893, in iter_ticks
    for i, val in enumerate(majorLocs)]
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/dates.py", line 395, in __call__
    dt = num2date(x, self.tz)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/dates.py", line 329, in num2date
    return _from_ordinalf(x, tz)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib-1.4.x-py2.7-linux-i686.egg/matplotlib/dates.py", line 218, in _from_ordinalf
    dt = datetime.datetime.fromordinal(ix)
ValueError: year is out of range

import numpy as np
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import matplotlib.dates as md
import datetime as dt

# create vectorized converter (can take list-like objects as arguments)
dateconv = np.vectorize(dt.datetime.fromtimestamp)

data = np.genfromtxt('testi.csv', delimiter=',', names=['t', 'btc', 'eur'])
plt.xkcd()

dates = dateconv(data['t']) # convert timestamps to datetime objects

plt.plot(dates, data['btc'], label='the data')
plt.xticks(dates, rotation=75, ha='right') # set ticks at plotted datetimes
ax=plt.gca()
xfmt = md.DateFormatter('%Y-%m-%d %H:%M:%S')
ax.xaxis.set_major_formatter(xfmt)

plt.tight_layout() # to make sure everything fits inside the figures boundaries

plt.savefig('testi2.png')