Book Image

Python Data Analysis

By : Ivan Idris
Book Image

Python Data Analysis

By: Ivan Idris

Overview of this book

Table of Contents (22 chapters)
Python Data Analysis
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Key Concepts
Online Resources
Index

NumPy


The following are useful NumPy functions:

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

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

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

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

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

  • numpy.load(file, mmap_mode=None): This function 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 the 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): This function loads data from a text file into a NumPy array.

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

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

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

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

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

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

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

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

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

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