python for data analysis 2nd edition

1.1. Foreword This way we use the memory analysis framework pandas to analyze the daily PV.1.2. Praise to Pandas In fact, personal to pandas this module is quite favorable. I use pandas to complete many of the day-to-day practical gadgets, such as the production of Excel reports, simple data migration, and so on. To me, pandas is a memory MySQL, I usually call him the program SQL. 1.3. Pandas

The tenth chapter of the book, "Python For Data Analysis", focuses on the processing of time series data.Label1. DateTime object, timestamp object, period object2. Two special indexes for pandas series and Dataframe object: Datetimeindex and Periodindex3. Time zone expression and processing4. Imestamp The frequency concept of object, period object, and its freque

)#Display OutputFigure () Gray () forIinchRange (File_len): Subplot (3,4,i + 1) pic= Immatrix[i].reshape (180,360) pic= Pic[::-1]#picshow = rot90 (pic,4)imshow (pic) Colorbar () show ()#Convert to sample populationX =Immatrix. T#get to this sizeM,n = X.shape[0:2]#obtain the average of each sampleMeanval = mean (X,axis =0)#Tempmean = Tile (Meanval, (64800,1))#Sample matrix de -CentralizedX = X-tile (Meanval, (64800,1))#Calculate covarianceS = dot (x.t,x)/(m-1)#calculate eigenvalues eg and eigenve

First, Brief introduction matplotlib1. Matplotlib is a powerful toolkit for Python drawing and data visualization2. Installation method: Pip Install Matplotlib3. Citation method: Import Matplotlib.pyplot as Plt4. Drawing function: Plt.plot ()5. Display Image: Plt.show () --Linetype LineStyle (-,-.,--,.. ) -colour color (b,g,r,y,k,w,... 2, plot function draw multiple curves 3, Pandas package

the string object method Split () method splits the string:The Strip () method removes whitespace and line breaks:Split () in combination with strip () using:The "+" symbol allows you to concatenate multiple strings together:The join () method is also the connection string, comparing it to the "+" symbol:The In keyword determines whether a string is contained in another string:The index () method and the Find () method determine the location of a substring: the difference between the index ()

;deff (x, y): -...return10*x+y + ... ->>> B = Np.fromfunction (f, (5,4), dtype=int) +>>>b AArray ([[[0, 1, 2, 3], at[10, 11, 12, 13], -[20, 21, 22, 23], -[30, 31, 32, 33], -[40, 41, 42, 43]]) ->>> b[2,3] -23 in>>> B[0:5, 1]#second column -Array ([1, 11, 21, 31, 41]) to>>> b[:, 1]#second column +Array ([1, 11, 21, 31, 41]) ->>> B[1:3,:]#second row, third row theArray ([[[10, 11, 12, 13], *[20, 21, 22, 23]]) $GT;GT;B[-1]#equivalent to B[-1,:], last linePanax NotoginsengArray ([40, 41, 42, 43])

After installing the NumPy module, I started to do a few small tests to run, but when I created numpy.py this filenumpy.pyimport numpyy = Numpy.array ([[[11,4,2],[2,6,1],[32,6,42]])print(y)After the operation error:Traceback (most recent):File "D:\Python_Reptile\numpy.py", line 1, Import NumPyFile "D:\Python_Reptile\numpy.py", line 2, y = Numpy.array ([[11,4,2],[2,6,1],[32,6,42]])Attributeerror:module ' NumPy ' has no attribute ' array 'Baidu opened the query for a long time, and the previous te

NumPy as the basis for the scientific calculation of Python, why Python is suitable for mathematical calculations, in addition to being easy to understand and easy to learn Python can simply invoke a large number of legacy libraries written in C and Fortran. The NumPy ndarray:a multidimensional Array Object Ndarray, which can be understood as an n-dimensional ar

C, C + +, FORTRAN code integration into Python tools Pandas: A large number of data structures and functions that handle structured data Precise indexing, reshaping, slicing, chopping, aggregating, selecting subsets High performance time series features and tools Matplotlib: The most popular library for plotting

ordered data such as time series, it may be necessary to do some interpolation when re-indexing, the method option can achieve this purpose:For ordered data such as time series, it may be necessary to do some interpolation when re-indexing, the method option can achieve this purpose: Method Parameter Introduction Parameters Description Ff

Before doing data analysis, many are using Oracle or MySQL, SQL to complete the query and statistical data analysis, but with the increase in data volume, the database with the development of a NoSQL database, due to the changes in the database and its underlying technology

DataFrame.hist(Data,Column=none,By=none,grid=true,Xlabelsize=none,Xrot=none,Ylabelsize=none,Yrot=none,Ax=none,Sharex=false,Sharey=false,Figsize=none,Layout=none,bins=10,**kwds)Data : DataFramecolumn : string or sequence strings or sequences by: object, optional If passed, then used to form histograms (histogram) for separate groups Grid : Boolean, default True grid line, defaul