Numpy详解:Python数据分析必备的高效数组库

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Numpy.pdf是一份全面介绍Python数据分析库Numpy的详细教程。Numpy是Python科学计算和数据分析领域的重要基石,它提供了一个高效且功能丰富的N维数组对象ndarray,以及通用的广播功能。这个库支持多维数组和矩阵操作,使得数据处理变得简单且速度快。 首先,Numpy的核心数据结构是ndarray,它是N维数组,所有的数据都在内存中连续存储,每个元素都有固定的大小,这与Python的列表(List)有着显著区别。ndarray支持多种数据类型,包括基本的布尔、数值(如整型、浮点型和复数)、字符串、字节序列等,这些类型都由Numpy的特定数据类型表示,例如np.int32、np.float64和np.complex128等。这些数据类型的选择会根据系统的平台自动调整以确保性能。 Numpy的基础部分主要讲解了如何创建、操作和理解ndarray。例如,通过np.array()函数可以将Python列表转换为Numpy数组,而数组的索引从0开始。此外,Numpy强调类型一致性,这意味着数组中的所有元素必须具有相同的类型。 除了基本的数组操作,Numpy还包含了一系列函数库,覆盖了广泛的功能。这部分内容包括但不限于: 1. 基础数学函数:如指数、对数、三角函数等,这些函数对ndarray中的元素进行操作,提供了高效的数学计算能力。 2. 随机数及概率函数:用于生成各种分布的随机数,这对于模拟和统计分析至关重要。 3. 统计函数:涵盖了常见的统计计算,如平均值、标准差、中位数等,用于数据清洗和预处理。 4. 线性代数函数:包括矩阵运算、向量操作、特征值和特征向量等,是解决线性问题的核心工具。 5. 傅里叶变换函数:处理信号处理和图像分析时,傅里叶变换是不可或缺的一部分。 Numpy.pdf是一份深入浅出的指南,不仅适合初学者快速掌握Numpy的基本用法,也适合经验丰富的开发者深入了解其强大的数学计算和数据处理能力。无论是数据分析还是机器学习项目,Numpy都是Python开发人员必备的技能之一。
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CONTENTS 1 Arrayobjects 3 1.1 TheN-dimensionalarray(ndarray).................................. 3 1.2 Scalars.................................................. 73 1.3 Datatypeobjects(dtype)........................................110 1.4 Indexing.................................................121 1.5 Standardarraysubclasses........................................125 1.6 Maskedarrays..............................................250 1.7 TheArrayInterface ...........................................433 2 Universalfunctions(ufunc) 439 2.1 Broadcasting...............................................439 2.2 Outputtypedetermination........................................440 2.3 Useofinternalbuffers..........................................440 2.4 Errorhandling..............................................440 2.5 CastingRules...............................................443 2.6 ufunc..................................................445 2.7 Availableufuncs.............................................452 3 Routines 457 3.1 Arraycreationroutines..........................................457 3.2 Arraymanipulationroutines.......................................488 3.3 Indexingroutines.............................................522 3.4 Datatyperoutines............................................547 3.5 Inputandoutput.............................................559 3.6 DiscreteFourierTransform(numpy.fft)...............................579 3.7 Linearalgebra(numpy.linalg) ...................................599 3.8 Randomsampling(numpy.random) .................................627 3.9 Sortingandsearching ..........................................678 3.10Logicfunctions..............................................691 3.11Binaryoperations.............................................707 3.12Statistics.................................................715 3.13Mathematicalfunctions .........................................735 3.14Functionalprogramming.........................................794 3.15Polynomials...............................................799 3.16Financialfunctions............................................812 3.17Setroutines................................................820 3.18Windowfunctions............................................825 3.19Floatingpointerrorhandling.......................................836 3.20Maskedarrayoperations.........................................842 i 3.21Numpy-specifichelpfunctions......................................962 3.22Miscellaneousroutines..........................................965 3.23TestSupport(numpy.testing)....................................966 3.24Asserts..................................................967 3.25Mathematicalfunctionswithautomaticdomain(numpy.emath)...................977 3.26Matrixlibrary(numpy.matlib)....................................977 3.27OptionallyScipy-acceleratedroutines(numpy.dual).........................977 3.28Numarraycompatibility(numpy.numarray).............................978 3.29OldNumericcompatibility(numpy.oldnumeric)..........................978 3.30C-TypesForeignFunctionInterface(numpy.ctypeslib)......................978 3.31Stringoperations.............................................979 4 Packaging(numpy.distutils) 1013 4.1 Modulesinnumpy.distutils....................................1013 4.2 BuildingInstallableClibraries......................................1024 4.3 Conversionof.srcfiles ........................................1025 5 NumpyC-API 1027 5.1 PythonTypesandC-Structures .....................................1027 5.2 Systemconfiguration...........................................1041 5.3 DataTypeAPI..............................................1043 5.4 ArrayAPI ................................................1045 5.5 UFuncAPI................................................1078 5.6 GeneralizedUniversalFunctionAPI...................................1083 5.7 Numpycorelibraries...........................................1085 6 Numpyinternals 1089 6.1 NumpyCCodeExplanations ......................................1089 6.2 Internalorganizationofnumpyarrays..................................1096 6.3 MultidimensionalArrayIndexingOrderIssues.............................1097 7 NumpyandSWIG 1099 7.1 Numpy.i:aSWIGInterfaceFileforNumPy...............................1099 7.2 Testingthenumpy.iTypemaps......................................1112 8 Acknowledgements 1115 Bibliography 1117 PythonModuleIndex 1123 Index 1125