How to set 'auto' for upper limit, but keep a fixed lower limit with matplotlib.pyplot
PythonMatplotlibPython Problem Overview
I want to set the upper limit of the y-axis to 'auto', but I want to keep the lower limit of the y-axis to always be zero. I tried 'auto' and 'autorange', but those don't seem to work. Thank you in advance.
Here is my code:
import matplotlib.pyplot as plt
def plot(results_plt,title,filename):
############################
# Plot results
# mirror result table such that each parameter forms an own data array
plt.cla()
#print results_plt
XY_results = []
XY_results = zip( *results_plt)
plt.plot(XY_results[0], XY_results[2], marker = ".")
plt.title('%s' % (title) )
plt.xlabel('Input Voltage [V]')
plt.ylabel('Input Current [mA]')
plt.grid(True)
plt.xlim(3.0, 4.2) #***I want to keep these values fixed"
plt.ylim([0, 80]) #****CHANGE**** I want to change '80' to auto, but still keep 0 as the lower limit
plt.savefig(path+filename+'.png')
Python Solutions
Solution 1 - Python
You can pass just left
or right
to set_xlim
:
plt.gca().set_xlim(left=0)
For the y axis, use bottom
or top
:
plt.gca().set_ylim(bottom=0)
Solution 2 - Python
Just set xlim
for one of the limits:
plt.xlim(left=0)
Solution 3 - Python
As aforementioned and according to the matplotlib documentation, the x-limits of a given axis ax
can be set using the set_xlim
method of the matplotlib.axes.Axes
class.
For instance,
>>> ax.set_xlim(left_limit, right_limit)
>>> ax.set_xlim((left_limit, right_limit))
>>> ax.set_xlim(left=left_limit, right=right_limit)
One limit may be left unchanged (e.g. the left limit):
>>> ax.set_xlim((None, right_limit))
>>> ax.set_xlim(None, right_limit)
>>> ax.set_xlim(left=None, right=right_limit)
>>> ax.set_xlim(right=right_limit)
To set the x-limits of the current axis, the matplotlib.pyplot
module contains the xlim
function that just wraps matplotlib.pyplot.gca
and matplotlib.axes.Axes.set_xlim
.
def xlim(*args, **kwargs):
ax = gca()
if not args and not kwargs:
return ax.get_xlim()
ret = ax.set_xlim(*args, **kwargs)
return ret
Similarly, for the y-limits, use matplotlib.axes.Axes.set_ylim
or matplotlib.pyplot.ylim
. The keyword arguments are top
and bottom
.
Solution 4 - Python
Just add a point on @silvio 's: if you use axis to plot like figure, ax1 = plt.subplots(1,2,1)
. Then ax1.set_xlim(xmin = 0)
also works!
Solution 5 - Python
The set_xlim
and set_ylim
permit None
values to achieve this. However, you must use the functions AFTER you have plotted the data. If you don't do this, it will use the default 0 for left/bottom and 1 for top/right. It does not recalculate the "automatic" limit each time you plot new data once you have set the limits.
import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot([0, 1, 4, 5], [3, 5, 6, 9])
ax.set_xlim(left=2, right=None)
ax.set_ylim(bottom=None, top=7)
plt.show()
(I.e., in the above example, if you would do ax.plot(...)
at the end, it won't give the desired effect.)
Solution 6 - Python
You can also do:
ax.set_xlim((None,upper_limit))
ax.set_xlim((lower_limit,None))
That is helpful if you want to use set(), which allows you to set several parameters at once:
ax.set(xlim=(None, 3e9), title='my_title', xlabel='my_x_label', ylabel='my_ylabel')