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+--- Thread: How to plot date series in matplotlib? (/thread-7783.html)
How to plot date series in matplotlib? - StrybolData - Jan-24-2018
I used the following code to format my series into timestamps, but I would like to now visualise it with pyplot. I based the format on the python datetime object, so to plot time with matplotlib I converted my column into a python datetime and then to the pyplot format...
Datetime format
spreads['Created at'] = pd.to_datetime(timedata).apply(lambda x:x.strftime('%H:%M:%S'))outcome : 07:20:00Next step pyplot format
> import matplotlib.pyplot as plt import random x = matplotlib.dates.date2num(spreads['Created at']) y = y = [i+random.gauss(0,1) for i,_ in enumerate(x)] plt.plot(x,y)AttributeError: 'str' object has no attribute 'toordinal'
Could somebody explain me what is wrong with my code?
RE: How to plot date series in matplotlib? - sparkz_alot - Jan-25-2018
Please post the error code in it's entirety and the code relevant to the error being thrown.
RE: How to plot date series in matplotlib? - StrybolData - Jan-25-2018
Ok the entire code:
import pandas as pd
spreads= pd.read_csv('data.csv',sep=',',encoding ="Latin-1")
spreads['Created at'] = pd.to_datetime(timedata, errors='coerce').apply(lambda x:x.strftime('%H:%M:%S'))
import matplotlib.pyplot as plt
import random
x = matplotlib.dates.date2num(spreads['Created at'])
y = [i+random.gauss(0,1) for i,_ in enumerate(x)]
plt.plot(x,y)The data of the csv is printed like this:0 07:20:00
1 07:20:00
2 07:20:00
3 07:20:00
4 07:20:00
5 07:35:00
6 08:42:00
7 12:28:00
The error:
Error:---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-79-7400273c000e> in <module>()
2 import random
3
----> 4 x = matplotlib.dates.date2num(spreads['Created at'])
5 y = [i+random.gauss(0,1) for i,_ in enumerate(x)]
6
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/dates.py in date2num(d)
360 if not d.size:
361 return d
--> 362 return _to_ordinalf_np_vectorized(d)
363
364
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/numpy/lib/function_base.py in __call__(self, *args, **kwargs)
2732 vargs.extend([kwargs[_n] for _n in names])
2733
-> 2734 return self._vectorize_call(func=func, args=vargs)
2735
2736 def _get_ufunc_and_otypes(self, func, args):
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/numpy/lib/function_base.py in _vectorize_call(self, func, args)
2802 res = func()
2803 else:
-> 2804 ufunc, otypes = self._get_ufunc_and_otypes(func=func, args=args)
2805
2806 # Convert args to object arrays first
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/numpy/lib/function_base.py in _get_ufunc_and_otypes(self, func, args)
2762
2763 inputs = [arg.flat[0] for arg in args]
-> 2764 outputs = func(*inputs)
2765
2766 # Performance note: profiling indicates that -- for simple
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/dates.py in _to_ordinalf(dt)
218 tzi = UTC
219
--> 220 base = float(dt.toordinal())
221
222 # If it's sufficiently datetime-like, it will have a `date()` method
AttributeError: 'str' object has no attribute 'toordinal'