Questions tagged [python]
Use for data science questions related to the programming language Python. Not intended for general coding questions (which should be asked on Stack Overflow).
6,581
questions
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What's the difference between fit and fit_transform in scikit-learn models?
I do not understand the difference between the fit and fit_transform methods in scikit-learn. Can anybody explain simply why we ...
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189
votes
1
answer
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Difference between isna() and isnull() in pandas
I have been using pandas for quite some time. But, I don't understand what's the difference between isna() and isnull(). And, ...
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150
votes
17
answers
126k
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Best python library for neural networks
I'm using Neural Networks to solve different Machine learning problems. I'm using Python and pybrain but this library is almost discontinued. Are there other good alternatives in Python?
139
votes
12
answers
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Why do people prefer Pandas to SQL?
I've been using SQL since 1996, so I may be biased. I've used MySQL and SQLite 3 extensively, but have also used Microsoft SQL Server and Oracle.
The vast majority of the operations I've seen done ...
127
votes
14
answers
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Python vs R for machine learning
I'm just starting to develop a machine learning application for academic purposes. I'm currently using R and training myself in it. However, in a lot of places, I have seen people using Python.
What ...
119
votes
2
answers
108k
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Training an RNN with examples of different lengths in Keras
I am trying to get started learning about RNNs and I'm using Keras. I understand the basic premise of vanilla RNN and LSTM layers, but I'm having trouble understanding a certain technical point for ...
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114
votes
12
answers
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SVM using scikit learn runs endlessly and never completes execution
I am trying to run SVR using scikit-learn (python) on a training dataset that has 595605 rows and 5 columns (features) while the test dataset has 397070 rows. The data has been pre-processed and ...
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94
votes
11
answers
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ValueError: Input contains NaN, infinity or a value too large for dtype('float32')
I got ValueError when predicting test data using a RandomForest model.
My code:
...
- 2,675
85
votes
6
answers
140k
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strings as features in decision tree/random forest
I am doing some problems on an application of decision tree/random forest. I am trying to fit a problem which has numbers as well as strings (such as country name) as features. Now the library, scikit-...
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73
votes
7
answers
82k
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Open source Anomaly Detection in Python
Problem Background:
I am working on a project that involves log files similar to those found in the IT monitoring space (to my best understanding of IT space). These log files are time-series data, ...
- 943
71
votes
9
answers
168k
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How to clone Python working environment on another machine?
I developed a machine learning model with Python (Anaconda + Flask) on my workstation and all goes well. Later, I tried to ship this program onto another machine where of course I tried to set up the ...
- 8,247
66
votes
9
answers
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Clustering geo location coordinates (lat,long pairs)
What is the right approach and clustering algorithm for geolocation clustering?
I'm using the following code to cluster geolocation coordinates:
...
- 803
66
votes
4
answers
145k
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What is the use of torch.no_grad in pytorch?
I am new to pytorch and started with this github code. I do not understand the comment in line 60-61 in the code ...
- 1,217
63
votes
9
answers
10k
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Tools and protocol for reproducible data science using Python
I am working on a data science project using Python.
The project has several stages.
Each stage comprises of taking a data set, using Python scripts, auxiliary data, configuration and parameters, and ...
- 761
59
votes
5
answers
53k
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Neural networks: which cost function to use?
I am using TensorFlow for experiments mainly with neural networks. Although I have done quite some experiments (XOR-Problem, MNIST, some Regression stuff, ...) now, I struggle with choosing the "...
- 713
56
votes
4
answers
41k
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Difference between OrdinalEncoder and LabelEncoder
I was going through the official documentation of scikit-learn learn after going through a book on ML and came across the following thing:
In the Documentation it is given about ...
- 693
52
votes
2
answers
428k
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train_test_split() error: Found input variables with inconsistent numbers of samples
Fairly new to Python but building out my first RF model based on some classification data. I've converted all of the labels into int64 numerical data and loaded into X and Y as a numpy array, but I am ...
- 623
48
votes
5
answers
100k
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Opening a 20GB file for analysis with pandas
I am currently trying to open a file with pandas and python for machine learning purposes it would be ideal for me to have them all in a DataFrame. Now The file is 18GB large and my RAM is 32 GB but I ...
- 481
46
votes
5
answers
44k
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How to force weights to be non-negative in Linear regression
I am using a standard linear regression using scikit-learn in python.
However, I would like to force the weights to be all non-negative for every feature. is there any way I can accomplish that? I was ...
- 1,941
45
votes
2
answers
72k
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Merging two different models in Keras
I am trying to merge two Keras models into a single model and I am unable to accomplish this.
For example in the attached Figure, I would like to fetch the middle layer $A2$ of dimension 8, and use ...
- 1,013
43
votes
6
answers
95k
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Calculating KL Divergence in Python
I am rather new to this and can't say I have a complete understanding of the theoretical concepts behind this. I am trying to calculate the KL Divergence between several lists of points in Python. I ...
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43
votes
2
answers
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What does from_logits=True do in SparseCategoricalcrossEntropy loss function?
In the documentation it has been mentioned that y_pred needs to be in the range of [-inf to inf] when from_logits=True. I truly ...
- 543
43
votes
4
answers
56k
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Multi GPU in Keras
How we can program in the Keras library (or TensorFlow) to partition training on multiple GPUs? Let's say that you are in an Amazon ec2 instance that has 8 GPUs and you would like to use all of them ...
- 569
38
votes
3
answers
192k
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Calculation and Visualization of Correlation Matrix with Pandas
I have a pandas data frame with several entries, and I want to calculate the correlation between the income of some type of stores. There are a number of stores with income data, classification of ...
- 535
37
votes
5
answers
27k
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Best practices to store Python machine learning models
What are the best practices to save, store, and share machine learning models?
In Python, we generally store the binary representation of the model, using pickle or joblib. Models, in my case, can be ...
- 471
36
votes
6
answers
83k
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Sentence similarity prediction
I'm looking to solve the following problem: I have a set of sentences as my dataset, and I want to be able to type a new sentence, and find the sentence that the new one is the most similar to in the ...
- 1,308
35
votes
6
answers
163k
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Merging multiple data frames row-wise in PySpark
I have 10 data frames pyspark.sql.dataframe.DataFrame, obtained from randomSplit as ...
- 1,147
35
votes
5
answers
60k
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Is it necessary to standardize your data before clustering?
Is it necessary to standardize your data before cluster? In the example from scikit learn about DBSCAN, here they do this in the line:
...
- 801
35
votes
1
answer
69k
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What is the best Keras model for multi-class classification?
I am working on research, where need to classify one of three event WINNER=(win, draw, lose)
...
- 547
33
votes
3
answers
44k
views
Hypertuning XGBoost parameters
XGBoost have been doing a great job, when it comes to dealing with both categorical and continuous dependant variables. But, how do I select the optimized parameters for an XGBoost problem?
This is ...
- 8,136
33
votes
1
answer
25k
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Ways to deal with longitude/latitude feature [closed]
I am working on a fictional dataset with 25 features. Two of the features are latitude and longitude of a place and others are pH values, elevation, windSpeed etc with varying ranges. I can perform ...
- 443
33
votes
4
answers
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How to use LeakyRelu as activation function in sequence DNN in keras?When it perfoms better than Relu?
How do you use LeakyRelu as an activation function in sequence DNN in keras?
If I want to write something similar to:
...
- 1,754
31
votes
8
answers
153k
views
How to count the number of missing values in each row in Pandas dataframe?
How can I get the number of missing value in each row in Pandas dataframe.
I would like to split dataframe to different dataframes which have same number of missing values in each row.
Any suggestion?...
- 2,857
30
votes
6
answers
21k
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What is the reason behind taking log transformation of few continuous variables?
I have been doing a classification problem and I have read many people's code and tutorials. One thing I've noticed is that many people take np.log or ...
- 601
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votes
4
answers
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Is pandas now faster than data.table?
Here is the GitHub link to the most recent data.table benchmark.
The data.table benchmarks has not been updated since 2014. I ...
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29
votes
3
answers
48k
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Keras Callback example for saving a model after every epoch?
Can someone please post a straightforward example of Keras using a callback to save a model after every epoch? I can find examples of saving weights, but I want to be able to save a completely ...
- 2,041
29
votes
2
answers
48k
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How to calculate the fold number (k-fold) in cross validation?
I am confused about how I choose the number of folds (in k-fold CV) when I apply cross validation to check the model. Is it dependent on data size or other parameters?
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28
votes
5
answers
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What is the benefit of splitting tfrecord file into shards?
I'm working on speech recognition with Tensorflow and plan to train LSTM NN with massive waves dataset. Because of the performance gains, I plan to use tfrecords. There are several examples on ...
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28
votes
5
answers
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VM image for data science projects
As there are numerous tools available for data science tasks, and it's cumbersome to install everything and build up a perfect system.
Is there a Linux/Mac OS image with Python, R and other open-...
- 421
28
votes
6
answers
3k
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Machine learning techniques for estimating users' age based on Facebook sites they like
I have a database from my Facebook application and I am trying to use machine learning to estimate users' age based on what Facebook sites they like.
There are three crucial characteristics of my ...
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28
votes
2
answers
12k
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Keras vs. tf.keras
I'm a bit confused in choosing between Keras (keras-team/keras) and tf.keras (tensorflow/tensorflow/python/keras/) for my new research project.
There is a debate that Keras isn't owned by anyone, so ...
- 1,195
28
votes
4
answers
46k
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Scikit-learn: Getting SGDClassifier to predict as well as a Logistic Regression
A way to train a Logistic Regression is by using stochastic gradient descent, which scikit-learn offers an interface to.
What I would like to do is take a scikit-learn's SGDClassifier and have it ...
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27
votes
5
answers
19k
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Improve the speed of t-sne implementation in python for huge data
I would like to do dimensionality reduction on nearly 1 million vectors each with 200 dimensions(doc2vec).
I am using TSNE ...
- 1,944
27
votes
3
answers
91k
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27
votes
4
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Is there a straightforward way to run pandas.DataFrame.isin in parallel?
I have a modeling and scoring program that makes heavy use of the DataFrame.isin function of pandas, searching through lists of facebook "like" records of ...
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votes
4
answers
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Word2Vec for Named Entity Recognition
I'm looking to use google's word2vec implementation to build a named entity recognition system. I've heard that recursive neural nets with back propagation through structure are well suited for named ...
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27
votes
1
answer
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PyTorch vs. Tensorflow Fold
Both PyTorch and Tensorflow Fold are deep learning frameworks meant to deal with situations where the input data has non-uniform length or dimensions (that is, situations where dynamic graphs are ...
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26
votes
7
answers
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Is Python a viable language to do statistical analysis in?
I originally came from R, but Python seems to be the more common language these days. Ideally, I would do all my coding in Python as the syntax is easier and I've had more real life experience using ...
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26
votes
4
answers
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Gradients for bias terms in backpropagation
I was trying to implement neural network from scratch to understand the maths behind it. My problem is completely related to backpropagation when we take derivative with respect to bias) and I ...
- 395
26
votes
5
answers
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Python library for segmented regression (a.k.a. piecewise regression)
I am looking for a Python library that can perform segmented regression (a.k.a. piecewise regression).
Example:
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