# How to plot histogram from list?

Given a list of numbers, such as `[5,3,6,1,...]`

, how can I create a histogram from them and show it directly in the notebook interface?

**Clarification:** 5, 3, 6, 1, ... should not be used for the heights of bars. Instead, the data should be binned first to create a histogram.

Given a list of pairs, such as `[[2,3], [4,5], ...]`

, how can I create a 2D histogram form them and show it as a plot similar to this? (I.e. clearly distinguish zero counts from small non-zero counts, and show it as a matrix plot, not as a 3D bar chart.)

**Clarification:** How can I use a colour scheme in `matrix_plot`

that will clearly differentiate between zero and non-zero values? E.g. use white for zero and some colour gradient for non-zero. `0`

and `0.0001`

should show clearly differently. How do I achieve this with the `cmap`

parameter?

R is good for visualizing statistics. It is included in sage: http://ask.sagemath.org/question/7805/how-to-use-r-with-sage/

@Thomas Thanks, that's probably what I will do.

As to your update on the cmap parameter, I think you may have to look for a cmap that does this. See http://matplotlib.org/examples/color/colormaps_reference.html and you can also design a custom cmap, see e.g. http://stackoverflow.com/questions/9707676/defining-a-discrete-colormap-for-imshow-in-matplotlib