Questions tagged [data-wrangling]

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when to drop na values? [on hold]

It's very basic question, but I wanted some clarity on this topic. Normally, I drop na values from columns if na values are less than 5% of total values. I wanted to ask, does this approach is ...
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0answers
36 views

Tools for reading data from large, irregular csv files (aka excel file hell)

I have a csv file with 1000 columns and 50 rows that was collected over a few months. Embedded randomly in the file are ~1000 small datasets with semi-standard formats (some columns differ, so does ...
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1answer
689 views

how to calculate number of datapoints within a given time interval?

I have a dataframe with one column which is a timestamp. I have converted that column to a datetime object using pandas to_datetime() method. However what I want is to ...
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3answers
45 views

How to deal with highly skewed (on counts) dependent variables?

I am working on a binary classification problem and the dataset consists of several variables which are count variables. For example, how many times a customer defaulted on a broadband bill payment in ...
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3answers
45 views

Can we use median to replace all the missing values from a column

If we can use the median to replace all of the missing values from a column, then what is the advantage of using median over mean for replacing the missing values in a column with numeric values?
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0answers
35 views

How to use zero-inflated negative binomial regression for binary classification task?

I am working on a binary classification problem and I am currently employing XGBoost. The dataset consists of several variables which are count variables. The problem is, these features are highly ...
3
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3answers
81 views

How to deal with count data in random forest

I am working on a classification model where my target class is a biased class with the class shape as 0 1 20694 101 Most of my features are the ...
2
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0answers
26 views

Data wrangling for a big set of docx files advice!

I'm looking for some advice on a data wrangling problem I'm trying to solve. I've spent a week solid taking different approaches and nothing seems to be quite perfect. Just FYI, this is my first big (...
3
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0answers
46 views

What should I do with the NaN values on this stock quote data?

I concatenated 3 stock quote data-frames all with date-time indexes. However, they differ in starting dates so the resulting data-frame contains NaN values for the stock quotes with more recent ...
1
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1answer
51 views

How to run KNN (or other) on nested features? Image metadata

I have looked everywhere and I can't find a straight solution. I have a set of metadata from images and their elements (name, heigh, width, position{top, right}). I ...
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0answers
35 views

Cleaning Excel Data in Merged Cells

I need to use an Excel file that have many merged cells with no specific order. I guess that the file creator thought that it would be more readable to merge the cells that have the same value. ...
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3answers
55 views

What is the correct procedure when “joining” data takes ~6 hours?

I am dealing with bike-share data. I have 2 DataFrames: trips_df (subset shown), total entries = ...
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3answers
22k views
3
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1answer
10k views

Populate column based on previous row with a twist

I'm struggling with a Pandas problem. I have the following data. ...
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9answers
7k views

How much of data wrangling is a data scientist's job?

I'm currently working as a data scientist at a retail company (my first job as a DS, so this question may be a result of my lack of experience). They have a huge backlog of really important data ...
2
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2answers
196 views

Technical name for this data wrangling process? Multiple columns into multi-factor single column

What is the technical name for the following data wrangling process? I want to collapse Table A into Table B. (To make the data suitable for ANOVA.) Table A: ...
2
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1answer
217 views

Inputting (a lot of )data into a dataframe one row at a time

I'm using python. Some 2D numpy arrays are stored in individual rows of a Series. They are 30x30 images. It looks something like this: ...
3
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2answers
67 views

Mean across every several rows in pandas

I have a table of features and labels where each row has a time stamp. Labels are categorical. They go in a batch where one label repeats several times. Batches with the same label do not have a ...
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0answers
24 views

What is the difference between 'if the data if of good quality' and 'if the data is tidy'?

I'm doing Data Analyst nanodegree from udacity. I'm confused between the difference even after going through the lecture a few times.
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0answers
19 views

How to work with string data with a lot of NAs in an aggregation task with R

I have recently taken up a data wrangling task and inherited a data from my predecessor which contains keyphrases extracted by hand like the following : ...
1
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1answer
5k views

removing special character from CSV file

I read my csv file as pandas dataframe. Originally it's a dict with multiple entries per keys. Its looks like this after reading as pandas dataframe: ...
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2answers
86 views

How do I split number string with digit pattern?

I am trying to split number string to two to digit numbers How do I get two different Numbers out that string Example: I want separate two numbers ...
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1answer
347 views

Unable to print in Jupyter Notebook using Pandas [closed]

I am doing basic data analysis on an csv file in jupyter notebook def answer_two(): return (df['Gold']-df['Gold.1']).argmax() answer_two The above code ...
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2answers
90 views

R Programming rearranging rows and colums from timeline data [closed]

I am new to R programming and data analytics. This is probably a trivial question but I could not find an answer. I'm also limited with my ontology of data science and data manipulation. So, I'm not ...
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2answers
76 views

Adoptive(Machine wise) ML packages

What kind of Machine Learning/Data Mining packages are available that can easily be scaled on a cluster. For instance H2O is one ...
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4answers
1k views

Which one is better performer on wrangling big data, R or Python?

I want to know which language/packages performs better & faster on wrangling big data? R and Python both has packages and libraries for wrangling and cleaning data. But which packages and ...
2
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2answers
115 views

How do you define the steps to explore the data? [closed]

I'm falling in love with data science and I'm spending a lot of time studying it. It seems that a common data science workflow is: Frame the problem Collect the data Clean the data Work on the data ...
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2answers
37 views

Analytics term for turning row values into column names and count its assigned values

Do we have a data mining/analysis term for turning row values into column names and count its assigned values?
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2answers
26k views

Sum up counts in a data.frame grouped by multiple variables

This is a snippet of the dataset I am currently working on: ...
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1answer
573 views

When to choose character instead of factor in R?

I am currently working on a dataset which contains a name attribute, which stands for a person's first name. After reading the csv file with ...
2
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2answers
207 views

Sort by average votes/ratings

I have a data set that's a dictionary of tuples. Each key represents an ID number and each tuple is (yesvotes, totalvotes). Example: ...
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2answers
404 views

Tools to perform SQL analytics on 350TB of csv data

In short, what would be the best method/tricks/techniques/tools for performing ad hoc sql (style) queries on 350TB of csv data? Would there be other options, tool wise that would do it faster if we ...
1
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1answer
186 views

Detecting boilerplate in text samples

I have a corpus of unstructured text that, due to a concatenation from different sources, has boilerplate metadata that I would like to remove. For example: DESCRIPTION PROVIDED BY AUTHOR: The goal ...