Questions tagged [tfidf]

tf–idf (term frequency–inverse document frequency), is a numerical statistic using in nlp that is intended to reflect how important a word is to a document in a collection or corpus. It is often used as a weighting factor in searches of information retrieval, text mining, and user modeling. tf–idf increases proportionally the number of times a word appears in the document.

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9 views

How can I use Ensemble learning of two models with different features as an input?

I have a fake news detection problem and it predicts the binary labels "1"&"0" by vectorizing the 'tweet' column, I use three different models for detection but I want to use ...
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Running PCA on top of tf-idf features?

Is it a good idea to run PCA on top of attributes obtained with Tf-Idf? The tf-idf returns a lot of attributes so in that case I believe it is a good idea to run PCA to reduce the number of dimensions....
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How do I get ngrams for all combinations of words in a sentence?

Lets say I have a sentence "I need multiple ngrams". If I create bigrams using Tf idf vectorizer it will create bigrams only using consecutive words. i.e. I will get "I need", &...
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Sparse matrix after vectorization giving size = 1

I am working on a NLP problem https://www.kaggle.com/c/nlp-getting-started. I want to perform vectorization after train_test_split but when I do that, the resulting ...
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TF-IDF to find technical terms

I have some sentences and I want to see whether or not they contain words that are technical terms. I was thinking of working with Wikipedia texts: finding the most common words in a certain article, ...
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43 views

tf-idf for sentence level features

Many papers mention comparing sentences using the tf-idf metric, e.g. Paper. They state: The first one is based on tf-idf where the value of the the corresponding dimension in the vector ...
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38 views

How to match a corpus with a string of words using a TF-IDF matrix?

I am trying to match strings of words with a website that has bulletpoints whose text is most similar to it. The way I thought of doing it is to get all of the documents from each bulletpoint into one ...
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35 views

Hashing trick for dimensionality reduction

I am building a model that uses TF-IDF NLP features in Spark Mllib. The TF-IDF HashingTF function in Mllib uses the 'hashing trick' to efficiently allocate terms to features. My question is: does the ...
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How does L1 normalisation work in Binary Classification?

I was working on a project where I was using TF*IDF algorithm. After applying grid search, I got the tfidf_norm=l1. Can someone explain how L1 normalisation form works in binary classification?(I have ...
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77 views

How to apply TFIDF in structured dataset in Python?

I know that TFIDF is an NLP method for feature extraction. and I know that there are libraries that calculate TFIDF directly from the text. This is not what I want though In my case, my text dataset ...
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Cosine Similarity: Works with TF-IDF Vectors OR with Probability Vectors?

Using Cosine Similarity is a common method to calculate Semantic Textual Similarity. And it is particularly useful when comparing Sentence Embeddings provided by the Universal Sentence Encoder. ...
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How to decide to go with BOW or TFIDF

I know that there are methods that help in selecting features such as Matual Info, and Info Gain, etc. But for datasets with thousands of records and thousands of features it is time consuming to ...
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Matching documents from different sets with tfidf and cosine distance

I have two different set of documents S1, S2, with 30 text documents each. Using some text representation method, such as tfidf ...
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How to create a big data frame in Python

I have a sparse matrix, $X$, created by TfidfVectorizer and its size is $(500000, 200000)$. I want to convert $X$ to a data frame but I'm always getting a memory error. I tried ...
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Integer encoding and weighing when one feature consists of more names [closed]

Hello I am trying to make a content based movie recommendation system and one feature is genre of the movie. I will give an integer number to each genre randomly. However, some movies are of more than ...
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When does it make sense to add numbers with different units?

Given two vectors containing numbers that have different natures / units, (example length in Meters and weight in Kilograms), does it make sense to calculate euclidean distance between these two ...
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Vector dimensionality seems to be implemented incorrectly

I'm trying to implement a fuzzy topic modeling approach in Python based on a paper, which is accommodated with an R implementation from GitHub. In one of the first steps a document term matrix is ...
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Classification using texts as features

I want to build a classification model to match customers and products. I have a description of each product, and a description of each customer, and the label : ...
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How to decide which method to use TFIDF, or BOW

In a huge dataset for NLP it is taking very long time to classify my dataset therefore, trying each feature extraction method separetly is time consuming and not effecient. Is there a way that can ...
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95 views

Why is the idf important in tf-idf when it seems to just re-scale your features?

I am trying to understand why tf-idf is useful. As I understand the formula to work out the tf-idf is: Can someone explain what is wrong with the reasoning below: Imagine I have 100 documents that ...
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Which would be an ideal model to get a specific sub string from a bigger string?

I have a corpus of documents whose some lines have information like this: wt 210 1b 14.4 oz (98 kg) or ...
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125 views

Why does using a standard scalar on my tf idf matrix make it perform better?

I have a TF-IDF matrix transformed on a list of tweets from a data set I am using. I have a pipeline where I initiate a StandardScalar and then next have my SVM with a linear kernel and auto gamma as ...
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Is normalizing term weight necessary when cosine similarity is used in retrieval?

When using cosine similarity in information retrieval, document vector length and query vector length are used for normalization. So if TF-IDF is used as a weighting function, then using raw frequency ...
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Can a term weighting function used in text retrieval be compared to one used in text classification?

I came up with a modified version of TF-IDF function for text retrieval task. I want to do retrieval experiments using Vector Space Model and compare my function to some of those proposed in the ...
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The TF-IDF is not matching with the bags of words

I am creating the information gains of all the words present in the vocabulary. However, when I check for feature names of the vectorizer it is different. For bag of words I am using: ...
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Building simple documents search engine

I'm having my first steps in the NLP and at the moment I'm looking forward to building my own documents search engine. I've already got to know with TFIDF in practical way and I've also read about ...
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53 views

Comparing TFIDF vectors of different shapes

I'm working on a project using TF-IDF vectors and agglomerative clustering -- the idea is that the corpus of documents increases over time, and when a new document is added, the mean cosine similarity ...
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261 views

Why I would use TF-IDF after Bag-of-Words (CountVectorizer)?

In my recent studies over Machine Learning NLP tasks I found this very nice tutorial teaching how to build your first text classifier: https://towardsdatascience.com/machine-learning-nlp-text-...
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SKLEARN SGDClassifier prediction accuracy hint?

There is a function predict but is it possible to also hint how much is the predicted category probable? Like prediction of category 1 with 90% confidence, or 2 with 30% confidence etc. Without this I ...
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SKLEARN GridSearchCV hinting higher accuracy than Pipeline but with same parameters as Pipeline estimators

I have pipeline estimators like this: ...
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Text Analysis : Recommendation to identify cause of loss from claim narrative documents

I am trying to analyze auto claims narrative documents which contain description about the accident usually free text written by claims executives. Is there a nlp technique I could use to identify ...
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107 views

Ordering of standardization, pca, and/or tfidf for neural network

I have 60k rows of text data. I have tokenized it into 55k columns. I am using a neural network to classify the data but have some questions about how to order my preprocessing steps. I have too much ...
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Is it good practice to remove the numeric values from the text data during preprocessing?

Im doing preprocessing on a text dataset. I have certain numerics in it like: date(1st July) year(2019) tentative values (3-5 years/ 10+ advantages). unique values (room no 31/ user rank 45) ...
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How to process the hyphenated english words for any nlp problem?

Im doing preprocessing on english text dataset. I encounter hyphenated words like 'well-known'. Will it be useful if I remove the hyphen as special character and treat it as a single word 'wellknown' ...
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TF-IDF for Topic Modeling

Can TF-IDF be used a sole method for Topic Modeling ? (I know there are better methods like LDA , LSA etc) I just want to understand if TF-IDF alone can help us in Topic modeling . If yes , can ...
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Word representation that gives more weight to terms frequent in corpus?

The tf-idf discounts the words that appear in a lot of documents in the corpus. I am constructing an anomaly detection text classification algorithm that is trained only on valid documents. Later I ...
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How does TF-IDF classify a document based on "Score" alloted to each word

I understand how TF-IDF "score" is calculated for each word in a document, but I do not get how can it be used to classify a test document. For example, if the word "Mobile" occurs ...
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177 views

How to handle unseen labels in test data?

I get something like TF-IDF of training corpus in python with (something like) TfidfVectorizer. In test data some features (here are the words of test corpus, every word is a feature) are not seen in ...
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How best to embed large and noisy documents

I have a large corpus of documents (web pages) collected from various sites of around 10k-30k chars each, I am processing them to extract relevant text as much as possible, but they are never perfect. ...
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How come same cluster category be separated?

I have these 200 vectors which were clustered using K-means clustering based on keywords weight similarity that was given by TF-IDF (Term Frequency - Inverse Document Frequency). The vectors were ...
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Is it accurate to say that "K-means clustering the vectors based on keywords weight similarity"?

Long story short, I have 200 vectors as a result of TF-IDF (Term Frequency - Inverse Document Frequency) on thousands of keywords in hundreds of vectors. The total number of unique keywords that I got ...
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What is the formula and log base for idf?

To calculate tf-idf, we do: tf*idf tf=number of times word occurs in document What is formula for idf and log base: Log(number of documents/number of documents containing the word) Log((1+number ...
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Topic alignment / topic modelling

What is the most efficient method for detecting whether the article is mostly about a specific topic, but without lots of data for training? My task is to determine how much a document is e.g. about ...
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Should I create a tfidf on a subset of a data set or use the whole corpus?

My goal in this project is to see if businesses on a list are currently customers within my organization. One piece of this involves producing a similarity score using cosine similarity on the names ...
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Semi-Supervised Learning using NLP

I am working on a drug reaction problem in which I need to extract tweets and label the tweets (binary-reaction due to drug or not). But since I don't have domain knowledge, and clustering would also ...
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Text vectorizer that capture feature offset in the text?

I'm using sklearn Tfifdfvectorizer to extract feature from text towards text classification. I believe the information I need tends to be in the beginning of the document, so I would like to somehow ...
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34 views

Solution for TF-IDF Vectorization in Angular project?

While making an Angular project to use my text-classification model on unseen data, i struggle in finding a way how to transform text to TFIDF features. Anyone faced same issue? Maybe a solution on ...
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ValueError: Found input variables with inconsistent numbers of samples: [2, 44] [closed]

Have a piece of code where i am cleaning the text from the 'Description' column and storing it as "cleaned" Then i create a ML model using the above as one of my features. ...