Questions tagged [data.table]

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1answer
52 views

how to see in pandas the element of a csv table with many columns (>30) which the names of its columns is more than 10 character?

how to see in pandas the element of a csv table with many columns (>25) which the names of its columns is more than 10 character? I have 5000 rows and 32 columns and the label of some columns are more ...
0
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0answers
21 views

Study resources for data manipulation interview questions

A colleague of mine is studying for tech roles, and they're asked to solve a consistent type of problem during the phone screenings: practicing manipulating data (sets, hash tables/dictionaries, ...
3
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3answers
9k views

How to Write Multiple Data Frames in an Excel Sheet

I have multiple data frames with same column names. I want to write them together to an excel sheet stacked vertically on top of each other. And between each, there will be a text occupying a row. ...
3
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2answers
75 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 ...
0
votes
1answer
33 views

Software for automated database processing

I faced a problem which I'd like to solve w/o any programming. And looking for a software to do this. I have a dataset, for example: (brand-id, brand-name, product-class-name;) ...
1
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2answers
490 views

Theoretical Question: Data.table vs Data.frame with Big Data

I know that I can read in a very large csv file much faster with fread using the data.table ...
3
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1answer
101 views

Look for previous date in dataframe that has certain column category in R

I have the following data frame: ...
2
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1answer
24 views

How to make smaller categories with factor character variables

I have this data set with consist of ISO3166 Alpha-2 codes for countries. Example: DE, AD, AE etc They are coded as factor variables in R and there are about 173 observations. Now because there are ...
3
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4answers
2k views

rows to columns in data.table R (or Python)

This is something I can't achieve with the reshape2 library for R. I have the following data: ...
-1
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1answer
894 views

R: Calculations based on frequencies / grouped / aggregate data

I am trying to do simple calculations in R when no raw data but grouped data with frequencies is available only. This is the case when I have a large amount of records in a database, say a large SQL ...
13
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4answers
12k views

Is pandas now faster than data.table?

https://github.com/Rdatatable/data.table/wiki/Benchmarks-%3A-Grouping The data.table benchmarks hasn't been updated since 2014. I heard somewhere that Pandas is ...
1
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0answers
34 views

Table function output and order of arguments

I have a silly question. Below is the output of a logistic regression analysis I did. I notice that when I switch the order of the arguments I put in the table function in R that it also switch the ...