numpy.histogram2d¶
-
numpy.
histogram2d
(x, y, bins=10, range=None, normed=None, weights=None, density=None)[source]¶ Compute the bi-dimensional histogram of two data samples.
Parameters: - x : array_like, shape (N,)
An array containing the x coordinates of the points to be histogrammed.
- y : array_like, shape (N,)
An array containing the y coordinates of the points to be histogrammed.
- bins : int or array_like or [int, int] or [array, array], optional
The bin specification:
- If int, the number of bins for the two dimensions (nx=ny=bins).
- If array_like, the bin edges for the two dimensions (x_edges=y_edges=bins).
- If [int, int], the number of bins in each dimension (nx, ny = bins).
- If [array, array], the bin edges in each dimension (x_edges, y_edges = bins).
- A combination [int, array] or [array, int], where int is the number of bins and array is the bin edges.
- range : array_like, shape(2,2), optional
The leftmost and rightmost edges of the bins along each dimension (if not specified explicitly in the bins parameters):
[[xmin, xmax], [ymin, ymax]]
. All values outside of this range will be considered outliers and not tallied in the histogram.- density : bool, optional
If False, the default, returns the number of samples in each bin. If True, returns the probability density function at the bin,
bin_count / sample_count / bin_area
.- normed : bool, optional
An alias for the density argument that behaves identically. To avoid confusion with the broken normed argument to
histogram
, density should be preferred.- weights : array_like, shape(N,), optional
An array of values
w_i
weighing each sample(x_i, y_i)
. Weights are normalized to 1 if normed is True. If normed is False, the values of the returned histogram are equal to the sum of the weights belonging to the samples falling into each bin.
Returns: - H : ndarray, shape(nx, ny)
The bi-dimensional histogram of samples x and y. Values in x are histogrammed along the first dimension and values in y are histogrammed along the second dimension.
- xedges : ndarray, shape(nx+1,)
The bin edges along the first dimension.
- yedges : ndarray, shape(ny+1,)
The bin edges along the second dimension.
See also
histogram
- 1D histogram
histogramdd
- Multidimensional histogram
Notes
When normed is True, then the returned histogram is the sample density, defined such that the sum over bins of the product
bin_value * bin_area
is 1.Please note that the histogram does not follow the Cartesian convention where x values are on the abscissa and y values on the ordinate axis. Rather, x is histogrammed along the first dimension of the array (vertical), and y along the second dimension of the array (horizontal). This ensures compatibility with
histogramdd
.Examples