Interpolate a 1-D function.
`x` and `y` are arrays of values used to approximate some function f: ``y = f(x)``. This class returns a function whose call method uses interpolation to find the value of new points.
Note that calling `interp1d` with NaNs present in input values results in undefined behaviour.
Parameters ---------- x : (N,) array_like A 1-D array of real values. y : (...,N,...) array_like A N-D array of real values. The length of `y` along the interpolation axis must be equal to the length of `x`. kind : str or int, optional Specifies the kind of interpolation as a string ('linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'previous', 'next', where 'zero', 'slinear', 'quadratic' and 'cubic' refer to a spline interpolation of zeroth, first, second or third order; 'previous' and 'next' simply return the previous or next value of the point) or as an integer specifying the order of the spline interpolator to use. Default is 'linear'. axis : int, optional Specifies the axis of `y` along which to interpolate. Interpolation defaults to the last axis of `y`. copy : bool, optional If True, the class makes internal copies of x and y. If False, references to `x` and `y` are used. The default is to copy. bounds_error : bool, optional If True, a ValueError is raised any time interpolation is attempted on a value outside of the range of x (where extrapolation is necessary). If False, out of bounds values are assigned `fill_value`. By default, an error is raised unless ``fill_value='extrapolate'``. fill_value : array-like or (array-like, array_like) or 'extrapolate', optional
- if a ndarray (or float), this value will be used to fill in for requested points outside of the data range. If not provided, then the default is NaN. The array-like must broadcast properly to the dimensions of the non-interpolation axes.
- If a two-element tuple, then the first element is used as a fill value for ``x_new < x
0`` and the second element is used for ``x_new > x-1``. Anything that is not a 2-element tuple (e.g., list or ndarray, regardless of shape) is taken to be a single array-like argument meant to be used for both bounds as ``below, above = fill_value, fill_value``.
.. versionadded:: 0.17.0
- If 'extrapolate', then points outside the data range will be extrapolated.
.. versionadded:: 0.17.0 assume_sorted : bool, optional If False, values of `x` can be in any order and they are sorted first. If True, `x` has to be an array of monotonically increasing values.
Attributes ---------- fill_value
Methods ------- __call__
See Also -------- splrep, splev Spline interpolation/smoothing based on FITPACK. UnivariateSpline : An object-oriented wrapper of the FITPACK routines. interp2d : 2-D interpolation
Examples -------- >>> import matplotlib.pyplot as plt >>> from scipy import interpolate >>> x = np.arange(0, 10) >>> y = np.exp(-x/3.0) >>> f = interpolate.interp1d(x, y)
>>> xnew = np.arange(0, 9, 0.1) >>> ynew = f(xnew) # use interpolation function returned by `interp1d` >>> plt.plot(x, y, 'o', xnew, ynew, '-') >>> plt.show()