python - strange error when plotting errorbars





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1















I'm trying to combine 3 datasets in one plot. Each dataset has it's own y and x error. I'm receiving this error message:



Traceback (most recent call last):
File "SED_plot.py", line 310, in <module>
plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/pyplot.py", line 2766, in errorbar
errorevery=errorevery, capthick=capthick, **kwargs)
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/axes/_axes.py", line 2749, in errorbar
in cbook.safezip(x, xerr[0])]
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/cbook.py", line 1479, in safezip
raise ValueError(_safezip_msg % (Nx, i + 1, len(arg)))
ValueError: In safezip, len(args[0])=16 but len(args[1])=48


when I run this code:



x0, y0          = x_val_all[0:16], y_val_all[0:16]
x0err, y0err = x_error_all[0:16], y_error_all[0:16]
x1, y1 = x_val_all[17:33], y_val_all[17:33]
x1err, y1err = x_error_all[17:33], y_error_all[17:33]
x2, y2 = x_val_all[33:49], y_val_all[33:49]
x2err, y2err = x_error_all[33:49], y_error_all[33:49]

plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
plt.errorbar(x0, y0, yerr=y0err, linestyle='None', ecolor="black", label= "Standard Deviation")
plt.errorbar(x1, y1, xerr=x1err, yerr=y1err, ecolor="red")
plt.errorbar(x2, y2, xerr=x2err, yerr=y2err, ecolor="purple")
plt.show()


Could it be that list slicing isn't working in this case? All the x values and y values are in one list each (x_val_all, y_val_all respectively) and so are the corresponding errors.



Sample code to reproduce:



import matplotlib.pyplot as plt

y = range(0,21,1)
x = range(0,21,1)
y_err = [0.5]*21

x_low = [0.7]*21
x_upper = [1.4]*21
x_err = [x_low, x_upper]


plt.errorbar(x[0:7],y[0:7], xerr=x_err[0:7], yerr=y_err[0:7], linestyle="none", color="black")
plt.errorbar(x[8:15],y[8:15], xerr=x_err[8:15], yerr=y_err[8:15], linestyle="none", color="red")

plt.show()









share|improve this question

























  • Can you post the full stacktrace? It helps narrow down where the error is occuring.

    – Andrew Guy
    Nov 17 '18 at 9:01











  • @AndrewGuy, sure just edited the question above.

    – Shaun
    Nov 17 '18 at 9:04











  • Works fine for me using some dummy data. I'm running Python 3.6 though.

    – Andrew Guy
    Nov 17 '18 at 10:13






  • 1





    Can you post a fully reproducible example? i.e. include some dummy data etc. That way someone can just copy and paste to try it out. I'm wondering if you've got a typo somewhere.

    – Andrew Guy
    Nov 17 '18 at 10:19






  • 1





    x_err has two elements, so you cannot index it with numbers like 7, 8 or 15.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 10:55


















1















I'm trying to combine 3 datasets in one plot. Each dataset has it's own y and x error. I'm receiving this error message:



Traceback (most recent call last):
File "SED_plot.py", line 310, in <module>
plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/pyplot.py", line 2766, in errorbar
errorevery=errorevery, capthick=capthick, **kwargs)
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/axes/_axes.py", line 2749, in errorbar
in cbook.safezip(x, xerr[0])]
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/cbook.py", line 1479, in safezip
raise ValueError(_safezip_msg % (Nx, i + 1, len(arg)))
ValueError: In safezip, len(args[0])=16 but len(args[1])=48


when I run this code:



x0, y0          = x_val_all[0:16], y_val_all[0:16]
x0err, y0err = x_error_all[0:16], y_error_all[0:16]
x1, y1 = x_val_all[17:33], y_val_all[17:33]
x1err, y1err = x_error_all[17:33], y_error_all[17:33]
x2, y2 = x_val_all[33:49], y_val_all[33:49]
x2err, y2err = x_error_all[33:49], y_error_all[33:49]

plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
plt.errorbar(x0, y0, yerr=y0err, linestyle='None', ecolor="black", label= "Standard Deviation")
plt.errorbar(x1, y1, xerr=x1err, yerr=y1err, ecolor="red")
plt.errorbar(x2, y2, xerr=x2err, yerr=y2err, ecolor="purple")
plt.show()


Could it be that list slicing isn't working in this case? All the x values and y values are in one list each (x_val_all, y_val_all respectively) and so are the corresponding errors.



Sample code to reproduce:



import matplotlib.pyplot as plt

y = range(0,21,1)
x = range(0,21,1)
y_err = [0.5]*21

x_low = [0.7]*21
x_upper = [1.4]*21
x_err = [x_low, x_upper]


plt.errorbar(x[0:7],y[0:7], xerr=x_err[0:7], yerr=y_err[0:7], linestyle="none", color="black")
plt.errorbar(x[8:15],y[8:15], xerr=x_err[8:15], yerr=y_err[8:15], linestyle="none", color="red")

plt.show()









share|improve this question

























  • Can you post the full stacktrace? It helps narrow down where the error is occuring.

    – Andrew Guy
    Nov 17 '18 at 9:01











  • @AndrewGuy, sure just edited the question above.

    – Shaun
    Nov 17 '18 at 9:04











  • Works fine for me using some dummy data. I'm running Python 3.6 though.

    – Andrew Guy
    Nov 17 '18 at 10:13






  • 1





    Can you post a fully reproducible example? i.e. include some dummy data etc. That way someone can just copy and paste to try it out. I'm wondering if you've got a typo somewhere.

    – Andrew Guy
    Nov 17 '18 at 10:19






  • 1





    x_err has two elements, so you cannot index it with numbers like 7, 8 or 15.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 10:55














1












1








1








I'm trying to combine 3 datasets in one plot. Each dataset has it's own y and x error. I'm receiving this error message:



Traceback (most recent call last):
File "SED_plot.py", line 310, in <module>
plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/pyplot.py", line 2766, in errorbar
errorevery=errorevery, capthick=capthick, **kwargs)
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/axes/_axes.py", line 2749, in errorbar
in cbook.safezip(x, xerr[0])]
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/cbook.py", line 1479, in safezip
raise ValueError(_safezip_msg % (Nx, i + 1, len(arg)))
ValueError: In safezip, len(args[0])=16 but len(args[1])=48


when I run this code:



x0, y0          = x_val_all[0:16], y_val_all[0:16]
x0err, y0err = x_error_all[0:16], y_error_all[0:16]
x1, y1 = x_val_all[17:33], y_val_all[17:33]
x1err, y1err = x_error_all[17:33], y_error_all[17:33]
x2, y2 = x_val_all[33:49], y_val_all[33:49]
x2err, y2err = x_error_all[33:49], y_error_all[33:49]

plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
plt.errorbar(x0, y0, yerr=y0err, linestyle='None', ecolor="black", label= "Standard Deviation")
plt.errorbar(x1, y1, xerr=x1err, yerr=y1err, ecolor="red")
plt.errorbar(x2, y2, xerr=x2err, yerr=y2err, ecolor="purple")
plt.show()


Could it be that list slicing isn't working in this case? All the x values and y values are in one list each (x_val_all, y_val_all respectively) and so are the corresponding errors.



Sample code to reproduce:



import matplotlib.pyplot as plt

y = range(0,21,1)
x = range(0,21,1)
y_err = [0.5]*21

x_low = [0.7]*21
x_upper = [1.4]*21
x_err = [x_low, x_upper]


plt.errorbar(x[0:7],y[0:7], xerr=x_err[0:7], yerr=y_err[0:7], linestyle="none", color="black")
plt.errorbar(x[8:15],y[8:15], xerr=x_err[8:15], yerr=y_err[8:15], linestyle="none", color="red")

plt.show()









share|improve this question
















I'm trying to combine 3 datasets in one plot. Each dataset has it's own y and x error. I'm receiving this error message:



Traceback (most recent call last):
File "SED_plot.py", line 310, in <module>
plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/pyplot.py", line 2766, in errorbar
errorevery=errorevery, capthick=capthick, **kwargs)
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/axes/_axes.py", line 2749, in errorbar
in cbook.safezip(x, xerr[0])]
File "/Library/Python/2.7/site-packages/matplotlib-override/matplotlib/cbook.py", line 1479, in safezip
raise ValueError(_safezip_msg % (Nx, i + 1, len(arg)))
ValueError: In safezip, len(args[0])=16 but len(args[1])=48


when I run this code:



x0, y0          = x_val_all[0:16], y_val_all[0:16]
x0err, y0err = x_error_all[0:16], y_error_all[0:16]
x1, y1 = x_val_all[17:33], y_val_all[17:33]
x1err, y1err = x_error_all[17:33], y_error_all[17:33]
x2, y2 = x_val_all[33:49], y_val_all[33:49]
x2err, y2err = x_error_all[33:49], y_error_all[33:49]

plt.errorbar(x0, y0, xerr=x0err, linestyle='None', ecolor="black", label= "Channel Width")
plt.errorbar(x0, y0, yerr=y0err, linestyle='None', ecolor="black", label= "Standard Deviation")
plt.errorbar(x1, y1, xerr=x1err, yerr=y1err, ecolor="red")
plt.errorbar(x2, y2, xerr=x2err, yerr=y2err, ecolor="purple")
plt.show()


Could it be that list slicing isn't working in this case? All the x values and y values are in one list each (x_val_all, y_val_all respectively) and so are the corresponding errors.



Sample code to reproduce:



import matplotlib.pyplot as plt

y = range(0,21,1)
x = range(0,21,1)
y_err = [0.5]*21

x_low = [0.7]*21
x_upper = [1.4]*21
x_err = [x_low, x_upper]


plt.errorbar(x[0:7],y[0:7], xerr=x_err[0:7], yerr=y_err[0:7], linestyle="none", color="black")
plt.errorbar(x[8:15],y[8:15], xerr=x_err[8:15], yerr=y_err[8:15], linestyle="none", color="red")

plt.show()






python matplotlib errorbar






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 17 '18 at 10:41







Shaun

















asked Nov 17 '18 at 7:30









ShaunShaun

1481314




1481314













  • Can you post the full stacktrace? It helps narrow down where the error is occuring.

    – Andrew Guy
    Nov 17 '18 at 9:01











  • @AndrewGuy, sure just edited the question above.

    – Shaun
    Nov 17 '18 at 9:04











  • Works fine for me using some dummy data. I'm running Python 3.6 though.

    – Andrew Guy
    Nov 17 '18 at 10:13






  • 1





    Can you post a fully reproducible example? i.e. include some dummy data etc. That way someone can just copy and paste to try it out. I'm wondering if you've got a typo somewhere.

    – Andrew Guy
    Nov 17 '18 at 10:19






  • 1





    x_err has two elements, so you cannot index it with numbers like 7, 8 or 15.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 10:55



















  • Can you post the full stacktrace? It helps narrow down where the error is occuring.

    – Andrew Guy
    Nov 17 '18 at 9:01











  • @AndrewGuy, sure just edited the question above.

    – Shaun
    Nov 17 '18 at 9:04











  • Works fine for me using some dummy data. I'm running Python 3.6 though.

    – Andrew Guy
    Nov 17 '18 at 10:13






  • 1





    Can you post a fully reproducible example? i.e. include some dummy data etc. That way someone can just copy and paste to try it out. I'm wondering if you've got a typo somewhere.

    – Andrew Guy
    Nov 17 '18 at 10:19






  • 1





    x_err has two elements, so you cannot index it with numbers like 7, 8 or 15.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 10:55

















Can you post the full stacktrace? It helps narrow down where the error is occuring.

– Andrew Guy
Nov 17 '18 at 9:01





Can you post the full stacktrace? It helps narrow down where the error is occuring.

– Andrew Guy
Nov 17 '18 at 9:01













@AndrewGuy, sure just edited the question above.

– Shaun
Nov 17 '18 at 9:04





@AndrewGuy, sure just edited the question above.

– Shaun
Nov 17 '18 at 9:04













Works fine for me using some dummy data. I'm running Python 3.6 though.

– Andrew Guy
Nov 17 '18 at 10:13





Works fine for me using some dummy data. I'm running Python 3.6 though.

– Andrew Guy
Nov 17 '18 at 10:13




1




1





Can you post a fully reproducible example? i.e. include some dummy data etc. That way someone can just copy and paste to try it out. I'm wondering if you've got a typo somewhere.

– Andrew Guy
Nov 17 '18 at 10:19





Can you post a fully reproducible example? i.e. include some dummy data etc. That way someone can just copy and paste to try it out. I'm wondering if you've got a typo somewhere.

– Andrew Guy
Nov 17 '18 at 10:19




1




1





x_err has two elements, so you cannot index it with numbers like 7, 8 or 15.

– ImportanceOfBeingErnest
Nov 17 '18 at 10:55





x_err has two elements, so you cannot index it with numbers like 7, 8 or 15.

– ImportanceOfBeingErnest
Nov 17 '18 at 10:55












2 Answers
2






active

oldest

votes


















1














Indexing x_err is the root cause of your error, as this is a list of two elements. My personal preference to fix this would be to use a list comprehension:



import matplotlib.pyplot as plt

y = range(0,21,1)
x = range(0,21,1)
y_err = [0.5]*21

x_low = [0.7]*21
x_upper = [1.4]*21
x_err = [x_low, x_upper]

plt.errorbar(x[0:7], y[0:7], xerr=[_x[0:7] for _x in x_err], yerr=y_err[0:7], linestyle="none", color="black")
plt.errorbar(x[8:15], y[8:15], xerr=[_x[8:15] for _x in x_err], yerr=y_err[8:15], linestyle="none", color="red")

plt.show()


(Note the use of _x within the list comprehension - list comprehension leaks into the local scope in Python 2.7, which would overwrite the earlier x variable if we used x as the variable within the comprehension.)



You could also do:



plt.errorbar(x[0:7], y[0:7], xerr=[x_err[0][0:7], x_err[1][0:7]], yerr=y_err[0:7], linestyle="none", color="black")
plt.errorbar(x[8:15], y[8:15], xerr=[x_err[0][8:15], x_err[1][8:15]], yerr=y_err[8:15], linestyle="none", color="red")


although this is a little more verbose.






share|improve this answer


























  • I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

    – Shaun
    Nov 17 '18 at 11:00













  • It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

    – Andrew Guy
    Nov 17 '18 at 11:04











  • your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

    – Shaun
    Nov 17 '18 at 11:09











  • Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

    – Andrew Guy
    Nov 17 '18 at 11:13






  • 1





    A general remark: Consider using numpy arrays instead of lists of lists.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 12:04



















1














Have a look at the docs you are presenting the x_error wrong, the list needs to be 2x7 however the way you slice it does does not produce that result. You are slicing a len 2 list with range 7. The code below gives you the plot you want



import matplotlib.pyplot as plt
y = range(0,21,1)
x = range(0,21,1)
y_err = [0.5]*21

x_low = [0.7]*21
x_upper = [1.4]*21
x_err = [x_low, x_upper]

fig, ax = plt.subplots()
idx = range(0, 16, 7)
for start, stop in zip(idx[:-1], idx[1:]):
ax.errorbar(x[start:stop], y[start:stop], y_err[start:stop],
[ i[start:stop] for i in x_err])


enter image description here



Edit: for errors like this I recommend using numpy as its array allow you to easily check dimension and index into them easier than lists of lists.






share|improve this answer


























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    2 Answers
    2






    active

    oldest

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    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1














    Indexing x_err is the root cause of your error, as this is a list of two elements. My personal preference to fix this would be to use a list comprehension:



    import matplotlib.pyplot as plt

    y = range(0,21,1)
    x = range(0,21,1)
    y_err = [0.5]*21

    x_low = [0.7]*21
    x_upper = [1.4]*21
    x_err = [x_low, x_upper]

    plt.errorbar(x[0:7], y[0:7], xerr=[_x[0:7] for _x in x_err], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[_x[8:15] for _x in x_err], yerr=y_err[8:15], linestyle="none", color="red")

    plt.show()


    (Note the use of _x within the list comprehension - list comprehension leaks into the local scope in Python 2.7, which would overwrite the earlier x variable if we used x as the variable within the comprehension.)



    You could also do:



    plt.errorbar(x[0:7], y[0:7], xerr=[x_err[0][0:7], x_err[1][0:7]], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[x_err[0][8:15], x_err[1][8:15]], yerr=y_err[8:15], linestyle="none", color="red")


    although this is a little more verbose.






    share|improve this answer


























    • I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

      – Shaun
      Nov 17 '18 at 11:00













    • It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

      – Andrew Guy
      Nov 17 '18 at 11:04











    • your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

      – Shaun
      Nov 17 '18 at 11:09











    • Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

      – Andrew Guy
      Nov 17 '18 at 11:13






    • 1





      A general remark: Consider using numpy arrays instead of lists of lists.

      – ImportanceOfBeingErnest
      Nov 17 '18 at 12:04
















    1














    Indexing x_err is the root cause of your error, as this is a list of two elements. My personal preference to fix this would be to use a list comprehension:



    import matplotlib.pyplot as plt

    y = range(0,21,1)
    x = range(0,21,1)
    y_err = [0.5]*21

    x_low = [0.7]*21
    x_upper = [1.4]*21
    x_err = [x_low, x_upper]

    plt.errorbar(x[0:7], y[0:7], xerr=[_x[0:7] for _x in x_err], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[_x[8:15] for _x in x_err], yerr=y_err[8:15], linestyle="none", color="red")

    plt.show()


    (Note the use of _x within the list comprehension - list comprehension leaks into the local scope in Python 2.7, which would overwrite the earlier x variable if we used x as the variable within the comprehension.)



    You could also do:



    plt.errorbar(x[0:7], y[0:7], xerr=[x_err[0][0:7], x_err[1][0:7]], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[x_err[0][8:15], x_err[1][8:15]], yerr=y_err[8:15], linestyle="none", color="red")


    although this is a little more verbose.






    share|improve this answer


























    • I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

      – Shaun
      Nov 17 '18 at 11:00













    • It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

      – Andrew Guy
      Nov 17 '18 at 11:04











    • your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

      – Shaun
      Nov 17 '18 at 11:09











    • Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

      – Andrew Guy
      Nov 17 '18 at 11:13






    • 1





      A general remark: Consider using numpy arrays instead of lists of lists.

      – ImportanceOfBeingErnest
      Nov 17 '18 at 12:04














    1












    1








    1







    Indexing x_err is the root cause of your error, as this is a list of two elements. My personal preference to fix this would be to use a list comprehension:



    import matplotlib.pyplot as plt

    y = range(0,21,1)
    x = range(0,21,1)
    y_err = [0.5]*21

    x_low = [0.7]*21
    x_upper = [1.4]*21
    x_err = [x_low, x_upper]

    plt.errorbar(x[0:7], y[0:7], xerr=[_x[0:7] for _x in x_err], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[_x[8:15] for _x in x_err], yerr=y_err[8:15], linestyle="none", color="red")

    plt.show()


    (Note the use of _x within the list comprehension - list comprehension leaks into the local scope in Python 2.7, which would overwrite the earlier x variable if we used x as the variable within the comprehension.)



    You could also do:



    plt.errorbar(x[0:7], y[0:7], xerr=[x_err[0][0:7], x_err[1][0:7]], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[x_err[0][8:15], x_err[1][8:15]], yerr=y_err[8:15], linestyle="none", color="red")


    although this is a little more verbose.






    share|improve this answer















    Indexing x_err is the root cause of your error, as this is a list of two elements. My personal preference to fix this would be to use a list comprehension:



    import matplotlib.pyplot as plt

    y = range(0,21,1)
    x = range(0,21,1)
    y_err = [0.5]*21

    x_low = [0.7]*21
    x_upper = [1.4]*21
    x_err = [x_low, x_upper]

    plt.errorbar(x[0:7], y[0:7], xerr=[_x[0:7] for _x in x_err], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[_x[8:15] for _x in x_err], yerr=y_err[8:15], linestyle="none", color="red")

    plt.show()


    (Note the use of _x within the list comprehension - list comprehension leaks into the local scope in Python 2.7, which would overwrite the earlier x variable if we used x as the variable within the comprehension.)



    You could also do:



    plt.errorbar(x[0:7], y[0:7], xerr=[x_err[0][0:7], x_err[1][0:7]], yerr=y_err[0:7], linestyle="none", color="black")
    plt.errorbar(x[8:15], y[8:15], xerr=[x_err[0][8:15], x_err[1][8:15]], yerr=y_err[8:15], linestyle="none", color="red")


    although this is a little more verbose.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited Nov 17 '18 at 11:16

























    answered Nov 17 '18 at 10:57









    Andrew GuyAndrew Guy

    4,1331630




    4,1331630













    • I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

      – Shaun
      Nov 17 '18 at 11:00













    • It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

      – Andrew Guy
      Nov 17 '18 at 11:04











    • your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

      – Shaun
      Nov 17 '18 at 11:09











    • Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

      – Andrew Guy
      Nov 17 '18 at 11:13






    • 1





      A general remark: Consider using numpy arrays instead of lists of lists.

      – ImportanceOfBeingErnest
      Nov 17 '18 at 12:04



















    • I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

      – Shaun
      Nov 17 '18 at 11:00













    • It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

      – Andrew Guy
      Nov 17 '18 at 11:04











    • your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

      – Shaun
      Nov 17 '18 at 11:09











    • Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

      – Andrew Guy
      Nov 17 '18 at 11:13






    • 1





      A general remark: Consider using numpy arrays instead of lists of lists.

      – ImportanceOfBeingErnest
      Nov 17 '18 at 12:04

















    I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

    – Shaun
    Nov 17 '18 at 11:00







    I see! is this the only way to handle varying asymmetric errors or is there a better way than constructing something like: x_err=[x_low,x_upr]

    – Shaun
    Nov 17 '18 at 11:00















    It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

    – Andrew Guy
    Nov 17 '18 at 11:04





    It doesn't seem an unreasonable way of doing it. I would just use list comprehension when trying to subscript these asymmetric errors.

    – Andrew Guy
    Nov 17 '18 at 11:04













    your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

    – Shaun
    Nov 17 '18 at 11:09





    your first suggestion (My personal preference...etc) isn't plotting the data correctly but the second one after that one does.

    – Shaun
    Nov 17 '18 at 11:09













    Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

    – Andrew Guy
    Nov 17 '18 at 11:13





    Ok, that's a bit odd - all 3 examples work the same in my environment. That could be a python version issue.

    – Andrew Guy
    Nov 17 '18 at 11:13




    1




    1





    A general remark: Consider using numpy arrays instead of lists of lists.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 12:04





    A general remark: Consider using numpy arrays instead of lists of lists.

    – ImportanceOfBeingErnest
    Nov 17 '18 at 12:04













    1














    Have a look at the docs you are presenting the x_error wrong, the list needs to be 2x7 however the way you slice it does does not produce that result. You are slicing a len 2 list with range 7. The code below gives you the plot you want



    import matplotlib.pyplot as plt
    y = range(0,21,1)
    x = range(0,21,1)
    y_err = [0.5]*21

    x_low = [0.7]*21
    x_upper = [1.4]*21
    x_err = [x_low, x_upper]

    fig, ax = plt.subplots()
    idx = range(0, 16, 7)
    for start, stop in zip(idx[:-1], idx[1:]):
    ax.errorbar(x[start:stop], y[start:stop], y_err[start:stop],
    [ i[start:stop] for i in x_err])


    enter image description here



    Edit: for errors like this I recommend using numpy as its array allow you to easily check dimension and index into them easier than lists of lists.






    share|improve this answer






























      1














      Have a look at the docs you are presenting the x_error wrong, the list needs to be 2x7 however the way you slice it does does not produce that result. You are slicing a len 2 list with range 7. The code below gives you the plot you want



      import matplotlib.pyplot as plt
      y = range(0,21,1)
      x = range(0,21,1)
      y_err = [0.5]*21

      x_low = [0.7]*21
      x_upper = [1.4]*21
      x_err = [x_low, x_upper]

      fig, ax = plt.subplots()
      idx = range(0, 16, 7)
      for start, stop in zip(idx[:-1], idx[1:]):
      ax.errorbar(x[start:stop], y[start:stop], y_err[start:stop],
      [ i[start:stop] for i in x_err])


      enter image description here



      Edit: for errors like this I recommend using numpy as its array allow you to easily check dimension and index into them easier than lists of lists.






      share|improve this answer




























        1












        1








        1







        Have a look at the docs you are presenting the x_error wrong, the list needs to be 2x7 however the way you slice it does does not produce that result. You are slicing a len 2 list with range 7. The code below gives you the plot you want



        import matplotlib.pyplot as plt
        y = range(0,21,1)
        x = range(0,21,1)
        y_err = [0.5]*21

        x_low = [0.7]*21
        x_upper = [1.4]*21
        x_err = [x_low, x_upper]

        fig, ax = plt.subplots()
        idx = range(0, 16, 7)
        for start, stop in zip(idx[:-1], idx[1:]):
        ax.errorbar(x[start:stop], y[start:stop], y_err[start:stop],
        [ i[start:stop] for i in x_err])


        enter image description here



        Edit: for errors like this I recommend using numpy as its array allow you to easily check dimension and index into them easier than lists of lists.






        share|improve this answer















        Have a look at the docs you are presenting the x_error wrong, the list needs to be 2x7 however the way you slice it does does not produce that result. You are slicing a len 2 list with range 7. The code below gives you the plot you want



        import matplotlib.pyplot as plt
        y = range(0,21,1)
        x = range(0,21,1)
        y_err = [0.5]*21

        x_low = [0.7]*21
        x_upper = [1.4]*21
        x_err = [x_low, x_upper]

        fig, ax = plt.subplots()
        idx = range(0, 16, 7)
        for start, stop in zip(idx[:-1], idx[1:]):
        ax.errorbar(x[start:stop], y[start:stop], y_err[start:stop],
        [ i[start:stop] for i in x_err])


        enter image description here



        Edit: for errors like this I recommend using numpy as its array allow you to easily check dimension and index into them easier than lists of lists.







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Nov 17 '18 at 11:14

























        answered Nov 17 '18 at 11:08









        GlobalTravelerGlobalTraveler

        690310




        690310






























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