vframes 0.1.0

A DataFrame library inspired by Python's Pandas. Should work on Linux, Windows and Mac (still testing)

Dependencies

VDuckDB ( https://github.com/rodabt/vduckdb )

Installation

v install rodabt.vduckdb
v install rodabt.vframes

Basic usage example

Before running the example please be sure to download the following files:

• people-500000.csv ( https://drive.google.com/uc?id=1gYcKeeF2KIx3jHsn-Egc_zjv-VaI4LFw&export=download )
• titanic.parquet ( https://www.timestored.com/data/sample/titanic.parquet )

import rodabt.vframes

// A convenience function for better printing
fn printlne(s string) {
    println('\n${s}\n')
}

fn main() {

    printlne("VFrames version: ${vframes.version()}")

    printlne("Initialize context in memory")
    mut ctx := vframes.init() // also you can provide a fixed location, i.e. 'ctx.db'
    
    printlne("Load 500.000 records from a CSV")
    df := ctx.read_auto('people-500000.csv')!
    
    printlne("Print first 5 records:")
    df.head(5)
    
    printlne("Assign first 10 records to variable x as []map[string]json2.Any")
    data := df.head(10, to_stdout: false)
    println(data)

    printlne("Print last 5 records:")
    df.tail(5)

    printlne("DataFrame info:")
    df.info()

    printlne("DataFrame shape: ${df.shape()}")

    printlne("Describe DataFrame:")
    df.describe()

    printlne("Create new DF with new column 'new_col'=Index*5, and select a subset of columns (Email, Phone, new_col):")
    df2 := df
        .add_column('new_col', 'Index*5')
        .subset(['Email','Phone','new_col'])  
    df2.head(10)

    printlne("Delete Email from new DF:")
    df3 := df2.delete_column('Email')
    df3.head(10)
    
    printlne("Load parquet (Titanic):")
    df4 := ctx.read_auto('titanic.parquet')!
    df4.head(10)

    printlne("Describe:")
    df4.describe()
    
    printlne("Average of Age and Fare by Sex and Embarked:")
    df5 := df4.group_by(['Sex','Embarked'],{"age_avg": "avg(Age)", "avg_fare": "avg(Fare)"})
    df5.head(10)
    
    printlne("Slice(2,3) of first DataFrame:")
    df6 := df.slice(2,3)
    df6.head(10)
    
    println("Reading a JSON file:")
    df7 := ctx.read_auto("data.json")
    df7.head()

    printlne("Error control: try to load a non valid file")
    _ := ctx.read_auto('no_valid.csv') or { 
        eprintln(err.msg())
        vframes.empty()
    }

    ctx.close()
}