normalization

问题 This question already has answers here : iphone sdk - Remove all characters except for numbers 0-9 from a string [duplicate] (3 answers) Closed 6 years ago . I'm new to Objective-C, but experienced in other higher languages. I want to normalize a string by removing all non-numeric characters. In other words given the input string "206-555-1212" the normalized result should be "2065551212". The code snippet below works, but given my experience in other languages that seems like overkill. Is

问题 There are several normalization methods to choose from. L1/L2 norm, z-score, min-max. Can anyone give some insights as to how to choose the proper normalization method for a dataset? I didn't pay too much attention to normalization before, but I just got a small project where it's performance has been heavily affected not by parameters or choices of the ML algorithm but by the way I normalized the data. Kind of surprise to me. But this may be a common problem in practice. So, could anyone

问题 I'm writing a simplified version of an email system on a site I'm creating. The basic premise is users can message each other on the site, best example would be ebay, you can message other users on the site itself and it basically acts as an email system. What I have is the messages themselves, who they're from, to and the text. I would also like to have basic "read/not read" and "deleted", possibly even "sent" categories. something like this: table structure: id, to, from, subject, body,

问题 If I have constructed a sparse matrix using the sparse(i, j, k) constructor, how can I then normalize the columns of the matrix (so that each column sums to 1)? I cannot efficiently normalize the entries before I create the matrix, so any help is appreciated. Thanks! 回答1: The easiest way would be a broadcasting division by the sum of the columns: julia> A = sprand(4,5,.5) A./sum(A,1) 4x5 Array{Float64,2}: 0.0 0.0989976 0.0 0.0 0.0795486 0.420754 0.458653 0.0986313 0.0 0.0 0.0785525 0.442349 0

问题 I am implementing a many-to-many mapping in grails using 3NF, Not using the hasMany or belongsTo property. Taken from this article it shows and explains quite a lot about its advantages. Article: http://burtbeckwith.com/blog/?p=169 Presentation notes: http://burtbeckwith.com/blog/files/169/gorm%20grails%20meetup%20presentation.pdf I'm trying to make a Tag system onto questions, kind of like this(stackoverflow :)) I can save the Question and the Tags, then save the association with them, but

问题 I'm attempting to create a function to normalize my arrays and it's expecting an output object that is structured like this: { allIds: [1], byId: { 1: {...} } } OR { allIds: ['1'], byId: { '1': {...} } } I'm trying to create an interface called IOutput to cater for this. I've tried this: interface IOutput { allIds: string[] | number[] byId: { [key: number | string]: any } } But it gives me the following error An index signature parameter type must be 'string' or 'number'. ts(1023) It seems to

问题 i have searched the web about normalizing tf grades on cases when the documents' lengths are very different (for example, having the documents lengths vary from 500 words to 2500 words) the only normalizing i've found talk about dividing the term frequency in the length of the document, hence causing the length of the document to not have any meaning. this method though is a really bad one for normalizing tf. if any, it causes the tf grades for each document to have a very large bias (unless

问题 I have seen in my past experience that most of the people don't use physical relationships in tables and they try to remember them and apply them through coding only. Here ' Physical Relationships ' refer to Primary Key , Foreign Key , Check constraints , etc. While designing a database, people try to normalize the database on paper and keep things documented. Like, if I have to create a database for a marketing company, I will try to understand its requirements. For example, what fields are

问题 I have seen in my past experience that most of the people don't use physical relationships in tables and they try to remember them and apply them through coding only. Here ' Physical Relationships ' refer to Primary Key , Foreign Key , Check constraints , etc. While designing a database, people try to normalize the database on paper and keep things documented. Like, if I have to create a database for a marketing company, I will try to understand its requirements. For example, what fields are

问题 I have a dataset which has 4 columns/attributes and 150 rows. I want to normalize this data using min-max normalization. So far, my code is: minData=min(min(data1)) maxData=max(max(data1)) minmaxeddata=((data1-minData)./(maxData)) Here, minData and maxData returns the global minimum and maximum values. Therefore, this code actually applies a min-max normalization over all values in the 2D matrix so that the global minimum is 0 and the global maximum is 1. However, I would like to perform the