Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
NumPy Functions' References
Index

Appendix C. NumPy Functions' References

This appendix contains a list of useful NumPy functions and their descriptions.

  • numpy.apply_along_axis(func1d, axis, arr, *args): Applies the function func1d along an axis on 1D slices of arr.

  • numpy.arange([start,] stop[, step,], dtype=None): Creates a NumPy array with evenly spaced values within a specified range.

  • numpy.argsort(a, axis=-1, kind='quicksort', order=None): Returns the indices that would sort the input array.

  • numpy.argmax(a, axis=None): Returns the indices of the maximum values along an axis.

  • numpy.argmin(a, axis=None): Returns the indices of the minimum values along an axis.

  • numpy.argwhere(a): Finds the indices of non-zero elements.

  • numpy.array(object, dtype=None, copy=True, order=None, subok=False, ndmin=0): Creates a NumPy array from an array-like sequence, such as a Python list.

  • numpy.testing.assert_allclose((actual, desired, rtol=1e-07, atol=0, err_msg='', verbose=True): Raises an error if two objects are unequal up to a specified precision.

  • numpy.testing.assert_almost_equal(): Raises an exception if two numbers are not equal up to a specified precision.

  • numpy.testing.assert_approx_equal(): Raises an exception if two numbers are not equal up to a certain significance.

  • numpy.testing.assert_array_almost_equal(): Raises an exception if two arrays are not equal up to a specified precision.

  • numpy.testing.assert_array_almost_equal_nulp(x, y, nulp=1): Compares arrays to their unit of least precision (ULP).

  • numpy.testing.assert_array_equal(): Raises an exception if two arrays are not equal.

  • numpy.testing.assert_array_less(): Raises an exception if two arrays do not have the same shape, and the elements of the first array are strictly less than the elements of the second array.

  • numpy.testing.assert_array_max_ulp(a, b, maxulp=1, dtype=None): Determines whether the array elements differ by, at most, a specified number of ULP.

  • numpy.testing.assert_equal(): Tests whether two NumPy arrays are equal.

  • numpy.testing.assert_raises(): Fails if a specified exception is not raised by a callable invoked with defined arguments.

  • numpy.testing.assert_string_equal(): Asserts that two strings are equal.

  • numpy.testing.assert_warns(): Fails if a specified warning is not thrown.

  • numpy.bartlett(M): Returns the Bartlett window with M points. This window is similar to a triangular window.

  • numpy.random.binomial(n, p, size=None): Draws random samples from the binomial distribution.

  • numpy.bitwise_and(x1, x2[, out]): Calculates the bit-wise AND of arrays.

  • numpy.bitwise_xor(x1, x2[, out]): Calculates the bit-wise XOR of arrays.

  • numpy.blackman(M): Returns a Blackman window with M points, which is close to optimal and a little bit worse than a Kaiser window.

  • numpy.column_stack(tup): Stacks 1D arrays provided as a tuple column wise.

  • numpy.concatenate ((a1, a2, ...), axis=0): Concatenates a sequence of arrays.

  • numpy.convolve(a, v, mode='full'): Computes the linear convolution of 1D arrays.

  • numpy.dot(a, b, out=None): Calculates the dot product of two arrays.

  • numpy.diff(a, n=1, axis=-1): Computes the nth difference for a given axis.

  • numpy.dsplit(ary, indices_or_sections): Splits an array into subarrays along the third axis.

  • numpy.dstack(tup): Stacks arrays given as a tuple along the third axis.

  • numpy.eye(N, M=None, k=0, dtype=<type 'float'>): Returns the identity matrix.

  • numpy.extract(condition, arr): Selects elements of an array using a condition.

  • numpy.fft.fftshift(x, axes=None): Shifts the zero-frequency component of a signal to the center of the spectrum.

  • numpy.hamming(M): Returns the Hamming window with M points.

  • numpy.hanning(M): Returns the Hanning window with M points.

  • numpy.hstack(tup): Stacks arrays given as a tuple horizontally.

  • numpy.isreal(x): Returns a Boolean array, where True corresponds to an element of the input array, which is a real number (as opposed to a complex number).

  • numpy.kaiser(M, beta): Returns a Kaiser window with M points for a given beta parameter.

  • numpy.load(file, mmap_mode=None): Loads NumPy arrays or pickled objects from .npy, .npz or pickles. A memory-mapped array is stored in the filesystem and doesn't have to be completely loaded in memory. This is especially useful for large arrays.

  • numpy.loadtxt(fname, dtype=<type 'float'>, comments='#', delimiter=None, converters=None, skiprows=0, usecols=None, unpack=False, ndmin=0): Loads data from a text file into a NumPy array.

  • numpy.lexsort (keys, axis=-1): Sorts using multiple keys.

  • numpy.linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None): Returns evenly spaced numbers over an interval.

  • numpy.max(a, axis=None, out=None, keepdims=False): Returns the maximum of an array along an axis.

  • numpy.mean(a, axis=None, dtype=None, out=None, keepdims=False): Calculates the arithmetic mean along the given axis.

  • numpy.median(a, axis=None, out=None, overwrite_input=False): Calculates the median along the given axis.

  • numpy.meshgrid(*xi, **kwargs): Returns coordinate matrices for coordinate vectors. For instance:

    In: numpy.meshgrid([1, 2], [3, 4])
    Out:
    [array([[1, 2],
            [1, 2]]), array([[3, 3],
            [4, 4]])]
  • numpy.min(a, axis=None, out=None, keepdims=False): Returns the minimum of an array along an axis.

  • numpy.msort(a): Returns a copy of an array sorted along the first axis.

  • numpy.nanargmax(a, axis=None): Returns the indices of the maximums given an axis ignoring NaNs.

  • numpy.nanargmin(a, axis=None): Returns the indices of the minimums given an axis ignoring NaNs.

  • numpy.nonzero(a): Returns indices of non-zero array elements.

  • numpy.ones(shape, dtype=None, order='C'): Creates a NumPy array of specified shape and data type, containing 1s.

  • numpy.piecewise(x, condlist, funclist, *args, **kw): Evaluates a function piecewise.

  • numpy.polyder(p, m=1): Differentiates a polynomial to a given order.

  • numpy.polyfit(x, y, deg, rcond=None, full=False, w=None, cov=False): Performs a least squares polynomial fit.

  • numpy.polysub(a1, a2): Subtracts polynomials.

  • numpy.polyval(p, x): Evaluates a polynomial at specified values.

  • numpy.prod(a, axis=None, dtype=None, out=None, keepdims=False): Returns the product of array elements over a specified axis.

  • numpy.ravel(a, order='C'): Flattens an array or returns a copy if necessary.

  • numpy.reshape(a, newshape, order='C'): Changes the shape of a NumPy array.

  • numpy.row_stack(tup): Stacks arrays row wise.

  • numpy.save(file, arr): Saves a NumPy array to a file in the NumPy .npy format.

  • numpy.savetxt(fname, X, fmt='%.18e', delimiter=' ', newline='\n', header='', footer='', comments='# '): Saves a NumPy array to a text file.

  • numpy.sinc(a): Computes the sinc function.

  • numpy.sort_complex(a): Sorts array elements with the real part first, then followed by the imaginary part.

  • numpy.split(a, indices_or_sections, axis=0): Splits an array into subarrays.

  • numpy.std(a, axis=None, dtype=None, out=None, ddof=0, keepdims=False): Returns the standard deviation along the given axis.

  • numpy.take(a, indices, axis=None, out=None, mode='raise'): Selects elements from an array using specified indices.

  • numpy.vsplit(a, indices_or_sections): Splits an array into subarrays vertically.

  • numpy.vstack(tup): Stacks arrays vertically.

  • numpy.where(condition, [x, y]): Selects array elements from input arrays based on a Boolean condition.

  • numpy.zeros(shape, dtype=float, order='C'): Creates a NumPy array of specified shape and data type, containing zeros.