텍스트 데이터 정리
Polars로 하는 데이터 변환
Liam Brannigan
Data Scientist & Polars Contributor
강사 소개
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- 리암 브래니건(Liam Brannigan), 수석 데이터 과학자
- ML 및 데이터 엔지니어링 전문가
- Polars 기여자
변환 엔진
이 과정이 맞으신가요?
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- Polars DataFrame 생성
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- Polars 표현식 사용
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- 그룹화 집계 수행
챕터 1
챕터 2
챕터 3
챕터 4
데이터셋 소개
import polars as pl
ratings = pl.read_csv("restaurant_ratings.csv")
shape: (5, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | f64 | f64 |
|------------------|--------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5.0 | 55.0 |
| Bang Bang Burger | Forest Rd. | restaurant | 4.0 | 55.0 |
| Costa Coffee | City Point | café | 5.0 | 41.0 |
| Costa Coffee | The Moorgate | takeaway | 5.0 | 0.0 |
| The Queens Head | Denman St. | bar | 5.0 | 187.0 |
레스토랑 추천 앱
shape: (3, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | f64 | f64 |
|------------------|--------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5.0 | 55.0 |
| Bang Bang Burger | Forest Rd. | restaurant | 4.0 | 55.0 |
| Costa Coffee | City Point | café | 5.0 | 41.0 |
- 공백 제거
- rating과 capacity 열 변환
- 고유 ID 열 생성
식별자 타입 캐스팅(표현식)
ratings.with_columns(
)
식별자 타입 캐스팅(표현식)
ratings.with_columns(
pl.col("rating").cast(pl.Int64)
)
shape: (5, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | i64 | f64 |
|------------------|--------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5 | 55.0 |
| Bang Bang Burger | Forest Rd. | restaurant | 4 | 55.0 |
| Costa Coffee | City Point | café | 5 | 41.0 |
| Costa Coffee | The Moorgate | takeaway | 5 | 0.0 |
| The Queens Head | Denman St. | bar | 5 | 187.0 |
여러 열 캐스팅
ratings.cast( )
여러 열 캐스팅
ratings.cast({ })
여러 열 캐스팅
ratings.cast({pl.Float64: pl.Int64})
shape: (5, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | i64 | i64 |
|------------------|--------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5 | 55 |
| Bang Bang Burger | Forest Rd. | restaurant | 4 | 55 |
| Costa Coffee | City Point | café | 5 | 41 |
| Costa Coffee | The Moorgate | takeaway | 5 | 0 |
| The Queens Head | Denman St. | bar | 5 | 187 |
텍스트 데이터 정리
shape: (5, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | i64 | i64 |
|------------------|-----------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5 | 55 |
| Bang Bang Burger | Forest Rd. | restaurant | 4 | 55 |
| Costa Coffee | City Point | café | 5 | 41 |
| Costa Coffee | The Moorgate | takeaway | 5 | 0 |
| The Queens Head | Denman St. | bar | 5 | 187 |
텍스트 데이터 정리
.str.contains().str.strip_chars().str.strip_chars_start().str.to_lowercase()- ...
텍스트 데이터 정리
.str.contains().str.strip_chars().str.strip_chars_start().str.to_lowercase()- ...
1 https://docs.pola.rs/api/python/stable/reference/expressions/string.html
텍스트 데이터 정리
.str.contains().str.strip_chars().str.strip_chars_start().str.to_lowercase()- ...
1 https://docs.pola.rs/api/python/stable/reference/expressions/string.html
텍스트 데이터 정리
ratings.with_columns(
)
텍스트 데이터 정리
ratings.with_columns(
pl.col("business")
)
텍스트 데이터 정리
ratings.with_columns(
pl.col("business").str.strip_chars_start()
)
shape: (5, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | i64 | i64 |
|------------------|--------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5 | 55 |
| Bang Bang Burger | Forest Rd. | restaurant | 4 | 55 |
| Costa Coffee | City Point | café | 5 | 41 |
| Costa Coffee | The Moorgate | takeaway | 5 | 0 |
| The Queens Head | Denman St. | bar | 5 | 187 |
텍스트 데이터 결합
shape: (5, 5)
| business | location | type | rating | capacity |
| --- | --- | --- | --- | --- |
| str | str | str | i64 | i64 |
|------------------|-----------------|------------|--------|----------|
| 7burgers | Wakey Wakey | restaurant | 5 | 55 |
| Bang Bang Burger | Forest Rd. | restaurant | 4 | 55 |
| Costa Coffee | City Point | café | 5 | 41 |
| Costa Coffee | The Moorgate | takeaway | 5 | 0 |
| The Queens Head | Denman St. | bar | 5 | 187 |
텍스트 데이터 결합
ratings.with_columns(
)
텍스트 데이터 결합
ratings.with_columns(
pl.concat_str(
)
텍스트 데이터 결합
ratings.with_columns(
pl.concat_str("business", "location"
)
텍스트 데이터 결합
ratings.with_columns(
pl.concat_str("business", "location", separator=":")
)
텍스트 데이터 결합
ratings.with_columns(
pl.concat_str("business", "location", separator=":").alias("id")
)
shape: (5, 5)
| business | location | type | ... | id |
| --- | --- | --- | --- | --- |
| str | str | str | ... | str |
|------------------|--------------|------------|-----|-------------------------------|
| 7burgers | Wakey Wakey | restaurant | ... | 7burgers:Wakey Wakey |
| Bang Bang Burger | Forest Rd. | restaurant | ... | Bang Bang Burger:Forest Rd. |
| Costa Coffee | City Point | café | ... | Costa Coffee:City Point |
| Costa Coffee | The Moorgate | takeaway | ... | Costa Coffee:The Moorgate |
| The Queens Head | Denman St. | bar | ... | The Queens Head:Denman St. |
연습해 봅시다!
Polars로 하는 데이터 변환
