Questions tagged [pyspark]

The Spark Python API (PySpark) exposes the apache-spark programming model to Python.

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5 views

Run ML model on a distributed manner on dataframe rdd partitions

When running a logistic regression on a large dataset with repartition, how do we stitch the results of the each partition results back to a dataframe to analyze. ...
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time syncronisation

Introduction Given is a vehicle which is moving past a station. If the vehicle passes the station (for simplicity determined by GPS) it sends RF-signals, to the station saying "Hello I am here ...
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14 views

Network flow dataset labeling

I have a network flow dataset with 500 mio. records that looks similar to this (highly simplified) ...
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1answer
44 views

PySpark Crossvalidation error

I want to do a very simple cross validation using LogisticRegression. Here is my code: ...
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0answers
241 views

Flattening of a structure field in pyspark is slow?

I am rather new to (py)spark. I am using a python UDF to compute several outputs. My idea was to pack all the values in a StructType and then flatten the structure before collecting the result. The ...
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48 views

Spark: How to run PCA parallelized? Only one thread used

I use pySpark and set my configuration like following: ...
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48 views

How to calculate latent vector for a user in ALS based on some new input?

So I have an ALS trained in pyspark but then I get some interactions from a new user that wasn't in the training set. I want to give recommendations to that new user without retraining the ALS based ...
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527 views

multi-label prediction with pySpark

I am new to Spark I am using pyspark to predict a multi label results. I have converted multi labels to binary So my labels will look like this ...
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1answer
282 views

PicklingError in pyspark (PicklingError: Can't pickle <class '__main__.Person'>: attribute lookup Person on __main__ failed)

I am unable to pickle the below class. I am using data bricks 6.5 ML (includes Apache Spark 2.4.5, Scala 2.11) ...
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1answer
21 views

Creating more than one worker nodes for local windows machine [closed]

I am using windows laptop. And I installed apache spark for my laptop. And I try to measure spark performance by changing spark components. because of that I want to create more than one worker nodes ...
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3answers
2k views

Remove all columns where the entire column is null

I have a very dirty csv where there are several columns with only null values. I would like to remove them. I am trying to select all columns where the count of null values in the column is not equal ...
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1answer
42 views

How to run Spark python code in Jupyter Notebook via command prompt

I am trying to import a data frame into spark using Python's pyspark module. For this, I used Jupyter Notebook and executed the code shown in the screenshot below After that I want to run this in CMD ...
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774 views

cannot access hive from spark [closed]

I am trying to install a hadoop + spark + hive cluster. I am using hadoop 3.1.2, spark 2.4.5 (scala 2.11 prebuilt with user-provided hadoop) and hive 2.3.3 (also tried 3.1.2 with the exact same ...
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1answer
127 views

Spark/Databricks: GPU does not appear to be utilized for ML regression (cross-validation, prediction) notebook

I have created and attached a notebook to a GPU-enabled Databricks cluster (6.4 ML (includes Apache Spark 2.4.5, GPU, Scala 2.11), EC2 type: p2.xlarge). I have started running the notebook that ...
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1answer
120 views

Pyspark Dataframes to Pandas and ML Ops - Parallel Execution Hold?

If I convert a spark dataframe into a pandas dataframe and subsequently apply pandas operations and sklearn models to the dataset in databricks, will the operations from pandas and sklearn be ...
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3answers
998 views

Is there a cost associated with converting Koalas dataframe to Spark dataframe?

I know that pandas works "under the hood" with numpy arrays stored in dictionaries. In contrast, Koalas works with the underlying Spark framework. Does that mean that there is no extra cost associated ...
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2answers
654 views

PySpark: How do I specify dropna axis in PySpark transformation?

I would like to drop columns that contain all null values using dropna(). With Pandas you can do this with setting the keyword argument ...
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1answer
208 views

How to apply K-Medoids in PySpark?

the pyspark ml library does not provide any clustering methods for K-Medoids. So my question is, how can one apply K-Medoids in a pyspark context?
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19 views

Tool/Technology/Framework to process file with 1GB [closed]

I'm new to datascience, but I have the following problem: 1) Read a file of 1GB, which each line is a json object 2) There are two more files, much smaller, which I need to JOIN some data In this ...
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1answer
172 views

How to split a CSV into a dataframe without newline

Currently I'm using pyspark to make my df from a csv. However when I take the data in, it puts each element on a new line. Is there any way to keep the elements separate, and keep them on the same ...
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0answers
282 views

Feature importance using logistic regression in pyspark

I am using logistic regression in PySpark. I have after splitting train and test dataset ...
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1answer
70 views

Incremental modelling of kmeans in pyspark

I have a large dataset and trained the model with kmeans for the first time. I saved the model and pipeline used . Now again I started collecting data. After sufficient data is collected using old ...
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1answer
328 views

Calculating Rank Ordering Error Metric for implicit recommendation

I'm reading Collaborative Filtering for Implicit Feedback Datasets. On page 6 they detail their evaluation strategy, which they define as mean Expected Percentile Ranking with the following formula: $...
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1answer
6k views

How to select multiple columns in a RDD with Spark (pySpark)?

Lets say I have a RDD that has comma delimited data. Each comma delimited value represents the amount of hours slept in the day of a week. So for i.e. [8,7,6,7,8,8,5] How can I manipulate the RDD so ...
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2answers
86 views

customer segmentation with unbalanced data

I am trying to do a customer segmentation on my transactional data and I am struggling a little bit on the best approach. Since it is an unsupervised model I can throw it to any algorithm and get some ...
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1answer
111 views

Which ML method for multiclass (non-binary) text classification should I choose (from SparkML)?

I am working on a quite big dataset that will be processed on the cluster, so this is why I am using PySpark for that purpose. The presentable records of this dataset have a such structure: ...
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1answer
85 views

How to store subset of columns from a csv file?

I need to create a table in hive (or Impala) by reading from a csv file (named file.csv), ...
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1answer
177 views

Pyspark Matrix Transformation

Let's assume I have the following dataframe in PySpark: ...
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0answers
52 views

How to read binary video format in HDFS using pyspark?

We want to work on detection of pedestrians in a video using ML algorithm.But the video is in the HDFS file system.How can we read the binary video file format from HDFS using spark? Please help me ...
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1answer
49 views

Regarding join in pyspark

Given a rdd in pyspark, $A=[(0, 1), (1, 2), (1, 3), (3, 0)]$ I am trying to find self join of A such that the second element of previous pair is equal to first element of next pair i.e. $...
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1answer
4k views

PicklingError: Could not serialize object: TypeError: can't pickle fasttext_pybind.fasttext objects

I built a fasttext classification model in order to do sentiment analysis for facebook comments (using pyspark 2.4.1 on windows). When I use the prediction model function to predict the class of a ...
5
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1answer
309 views

Pyspark: Filter dataframe based on separate specific conditions

How can I select only certain entries that match my condition and from those entries, filter again using regex? For instance, I have this dataframe (df) ...
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0answers
64 views

Where is $SPARK_HOME on an EC2 instance?

I am working on an EC2 instance with anaconda and pyspark pre-installed. My $SPARK_HOME variable is not set. Any ideas on how to locate my spark home?
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2answers
205 views

Record Linkage problem

I am building Matching Alogoritm using ML.Project is to match Internal customer data with external customer data.Features are names,address,city,state and zip. We create pairs between data sets and ...
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1answer
559 views

Pyspark Pipeline Custom Transformer

I'm having some trouble understanding the creation of custom transformers for Pyspark pipelines. I am writing a custom transformer that will take the dataframe column Company and remove stray commas: ...
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112 views

I got a overall mean average precision score of 0 for a recommendation engine

I just wanted to know if receiving an overall MAP score of 0 in a recommendation engine was possible, or a sign that my calculation or my logic for the engine was wrong.
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2answers
884 views

Model ensemble with Spark or Scikit Learn

I am using Spark MLLib to make prediction and I would like to know if it is possible to create your custom Estimators. Here is a reproducible of what I would like my model to do with the Spark api <...
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1answer
1k views

Getting parameters of the best model with crossvalidation in with SparkMLLib

I am having trouble accessing the parameters of estimators of model in SparkMLlib. More precisely my problem is: I have a logistic regression model for which I want to find the best regularization ...
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2answers
981 views

K-modes implementation in pyspark

I'm looking for an implementation of k-modes in pyspark. I found this and this as implementations. First, I tried implementing k-modes using the first link and faced issues. So I went ahead and tried ...
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0answers
71 views

Obtain learning curve of Gradient Boosted Tree model in PySpark

Currently there seems to be no method in PySpark of checkpointing the performance of a model at each gradient update. Is there a way to get the performance of a model at each gradient update so that a ...
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1answer
215 views

Null predictions for ALS in Pyspark

I am trying to read from my dataset which has three coloumns. (User, Repository and Number of Stars) In[10] ...
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1answer
9k views

Spark DataFrame “Limit” function takes too much time to display result

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2answers
2k views

PySpark v Pandas Dataframe Memory Issue

Suppose I have a csv file with 20k rows, which I import into Pandas dataframe. I then run models like Random Forest or Logistic Regression from sklearn package and it runs fine. However, when I import ...
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0answers
519 views

What is the difference between PySpark's featuresCol, labelCol, predictionCol, and probabilityCol?

I am attempting to train a random forest classifier (pyspark.ml.classification.RandomForestClassifier) on a large dataset (~70gb). However, I am not sure what to ...
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1answer
672 views

Using keras tokenizer on Spark DataFrame. Column is not iterable [closed]

I am having trouble using the Tokenizer The code is ...
2
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1answer
196 views

alternatives to pyspark to query a csv file locally (no distributed computation needed)

I am reading a csv file with pyspark to extract some information from it. I am running pyspark locally and I do not need distributed computation. On the contrary I need some plotting library such as ...
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0answers
15 views

Is there a built-in pyspark function for the paradigm union(filter, take)? [closed]

Essentially, filtering by key, taking a specific number (based on key) from the DataFrame, and unioning these results for a number of values. For example, ...
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1answer
56 views

Best Data Science & Machine Learning Conferences 2019? [closed]

What are the best data science conferences you have attended? I am looking for a conference that will help me further develop my Data Science and Machine Learning competencies. Topics that are ...
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2answers
3k views

Why is there a difference of “ML” vs “MLLIB” in Apache Spark's documentation?

I am trying to figure out which pyspark library to use with Word2Vec and I'm presented with two options according to the pyspark documentation. https://spark.apache.org/docs/2.2.0/mllib-feature-...
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1answer
1k views

cosine similarity between items (purchase data) and normalisation

I'm using IndexedRowMatrix which represents the products's user purchase behaviours and in order to build product recommendations, I use cosine similarity to calculate similarities between products. ...