Polars是一个用于操作结构化数据的高性能DataFrame库,可以用来进行数据清洗和格式转换、数据分析和统计、数据可视化、数据读取和存储、数据合并和拼接等等,相当于Rust版本的Pandas库。 Polars读写数据支持如下: 常见数据文件:csv、parquet(不支持xlsx、json文件) 云存储:S3、Azure Blob、BigQuery 数...
类型转换(Casting)将列的底层 DataType 转换为新的数据类型。Polars 使用 Arrow 在内存中管理数据,并依赖于 Rust 实现中的计算核心 来执行转换。类型转换通过 cast() 方法实现。 cast 方法包括一个 strict 参数,该参数确定当 Polars 遇到无法从源 DataType 转换为目标 DataType 的值时的行为。默认情况下,strict=...
() for column_name in arrow_table.schema.names: column = arrow_table[column_name] # 检查每个列的空值数量 null_count = column.null_count if null_count > 0: print(f"列 '{column_name}' 包含 {null_count} 个空值。") return False else: print(f"没有空值。") return True def write_...
Dropping column a changes the column list but not reflected in the call to columns. If you comment out the drop_in_place you end up with 3 entries in columns, but only 1 if you drop_in_place a Expected behavior Should the df.columns in the line 19 access to the list provide both b...
The memory-use should stabilize; like it happens for the callback with pandas. Installed versions ---Version info--- Polars: 1.4.1 Index type: UInt32 Platform: Windows-10-10.0.19045-SP0 Python: 3.11.3 (tags/v3.11.3:f3909b8, Apr 4 2023, 23:49:59) [MSC v.1934 64 bit (AMD64)]...
apply( // 在select、with_column、with_columns 上下文下调用 apply |s| { let s: &ChunkedArray<Int32Type> = s.i32()?; let out: Int32Chunked = s.into_iter().map(|v| match v { Some(v_) => Some(v_ * 10), _ => None, }).collect(); Ok(Some(out.into_series())) }, Get...
如书中所述，Object数据的支持有限。在这里，你遇到了其中的一个限制，因为python字典的集合不是Arrow...
Column NamePolars Data TypeDescription record_id Int64 (i64) Unique row identifier total Float64 (f64) Bill total tip Float64 (f64) Tip given gender String (str) Diner’s gender smoker Boolean (bool) Diner’s smoker status day String (str) Day of meal time String (str) Time of meal...
I have a dict and a polars DataFrame and want to map one column to the values of the dict: import polars as pl df = pl.DataFrame({ 'label': ['AA', 'BB', 'AA', 'CC'], 'type': ['CASH', 'ITEM', 'CHECK', 'CHECK'], }) mapping = { 'CASH': {'qty': 1, 'origin': ...
Modern style type hints for the test suite by @stinodego inhttps://github.com/pola-rs/polars/pull/3949 Fixed mostSee Alsodocstring formatting, quietened the last warnings coming fromdoctestsby @alexander-beedie inhttps://github.com/pola-rs/polars/pull/3932 ...