A small but important detail for adjusting figure size on a one-off basis (as several commenters above reported "this doesn't work for me"):
You should do plt.figure(figsize=(,)) PRIOR to defining your actual plot. For example:
This should correctly size the plot according to your specified figsize:
values = [1,1,1,2,2,3]
_ = plt.figure(figsize=(10,6))
_ = plt.hist(values,bins=3)
plt.show()
Whereas this will show the plot with the default settings, seeming to "ignore" figsize:
values = [1,1,1,2,2,3]
_ = plt.hist(values,bins=3)
_ = plt.figure(figsize=(10,6))
plt.show()