Presentación del modo lazy

Introducción a Polars

Liam Brannigan

Data Scientist & Polars Contributor

Modo eager

(
    pl.read_csv("vacation_rentals.csv")


)

Carga el CSV en un DataFrame

Modo lazy

Modo eager

(
    pl.read_csv("vacation_rentals.csv")


)

Carga el CSV en un DataFrame

Modo lazy

(
    pl.scan_csv("vacation_rentals.csv")


)

Inicia el plan de consulta
Lee las primeras filas del CSV

Modo eager

(
    pl.read_csv("vacation_rentals.csv")


)

| name     | type    | ... | beach |
| ---      | ---     | ... | ---   |
| str      | str     | ... | bool  |
|----------|---------| ... |-------|
| Waves    | Cottage | ... | false |
| Seashell | Cottage | ... | true  |
| ...      | ...     | ... | ...   |

Modo lazy

(
    pl.scan_csv("vacation_rentals.csv")


)

naive plan: 

Csv SCAN [vacation_rentals.csv]
PROJECT */8 COLUMNS

Modo eager

(
    pl.read_csv("vacation_rentals.csv")
    .select("name","price")

)

Modo lazy

Modo eager

(
    pl.read_csv("vacation_rentals.csv")
    .select("name","price")

)

Modo lazy

(
    pl.scan_csv("vacation_rentals.csv")
    .select("name","price")

)

Actualiza el plan de consulta
Optimiza el plan de consulta

Plan de consulta optimizado

print(
    pl.scan_csv("vacation_rentals.csv")
    .select("name","price")
    .explain()
)

Csv SCAN [vacation_rentals.csv]

PROJECT 2/8 COLUMNS

Optimización: projection pushdown

Ejecutar una consulta lazy

(
    pl.scan_csv("vacation_rentals.csv")
    .select("name","price")
    .collect()
)

shape: (49, 2)
| name      | price |
| ---       | ---   |
| str       | i64   |
|-----------|-------|
| Waves     | 540   |
| Seashells | 540   |
| ...       | ...   |

Modo eager vs. modo lazy

(
    pl.read_csv("vacation_rentals.csv")
    .select("name","price")

)

Paso a paso

(
    pl.scan_csv("vacation_rentals.csv")
    .select("name","price")
    .collect()
)

Consulta completa

Modo eager vs. modo lazy

Un oso Polar corriendo y un oso Polars durmiendo

paso a paso: modo eager
depuración: modo eager
rendimiento optimizado: modo lazy

¡Vamos a practicar!

Introducción a Polars