11.6.2. astroML.stats.binned_statistic_2d¶
- astroML.stats.binned_statistic_2d(x, y, values, statistic='mean', bins=10, range=None)¶
Compute a bidimensional binned statistic for a set of data.
This is a generalization of a histogram2d function. A histogram divides the space into bins, and returns the count of the number of points in each bin. This function allows the computation of the sum, mean, median, or other statistic of the values within each bin.
Parameters : x : array_like
A sequence of values to be binned along the first dimension.
y : array_like
A sequence of values to be binned along the second dimension.
values : array_like
The values on which the statistic will be computed. This must be the same shape as x.
statistic : string or callable, optional
The statistic to compute (default is ‘mean’). The following statistics are available:
- ‘mean’ : compute the mean of values for points within each bin. Empty bins will be represented by NaN.
- ‘median’ : compute the median of values for points within each bin. Empty bins will be represented by NaN.
- ‘count’ : compute the count of points within each bin. This is identical to an unweighted histogram. values array is not referenced.
- ‘sum’ : compute the sum of values for points within each bin. This is identical to a weighted histogram.
- function : a user-defined function which takes a 1D array of values, and outputs a single numerical statistic. This function will be called on the values in each bin. Empty bins will be represented by function([]), or NaN if this returns an error.
bins : int or [int, int] or array-like or [array, array], optional
The bin specification:
- the number of bins for the two dimensions (nx=ny=bins),
- the number of bins in each dimension (nx, ny = bins),
- the bin edges for the two dimensions (x_edges=y_edges=bins),
- the bin edges in each dimension (x_edges, y_edges = bins).
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.
Returns : statistic : ndarray, shape(nx, ny)
The values of the selected statistic in each two-dimensional bin
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
np.histogram2d, binned_statistic, binned_statistic_dd