在`polars::prelude::DataFrame`中找不到lazy()方法

Question

我正在 Rust 中为 Polars 编写一个外部库（供Raku::Dan使用），并且想通过调用 df.lazy() 为 LazyFrame 对象获取一个不透明容器。

use polars::prelude::*;//{CsvReader, DataType, DataFrame, Series};
use polars::prelude::{Result as PolarResult};
use polars_lazy::prelude::*;

// LazyFrame Container

pub struct LazyFrameC {
    lf: LazyFrame,
}

impl LazyFrameC {
    fn new(ptr: *mut DataFrameC) -> LazyFrameC {
        LazyFrameC {
            lf: (*ptr).df.lazy(),
        }
    }
}
// extern functions for LazyFrame Container
#[no_mangle]
pub extern "C" fn lf_new(ptr: *mut DataFrameC) -> *mut LazyFrameC {
    let df_c = unsafe {
        assert!(!ptr.is_null());
        &mut *ptr
    };

    Box::into_raw(Box::new(LazyFrameC::new(ptr)))
}

不起作用，给出错误：

error[E0599]: no method named `lazy` found for struct `polars::prelude::DataFrame` in the current scope
   --> src/lib.rs:549:27
    |
549 |             lf: (*ptr).df.lazy(), 
    |                           ^^^^ method not found in `polars::prelude::DataFrame`

这是我的 Cargo.toml（编辑）...

error[E0599]: no method named `lazy` found for struct `polars::prelude::DataFrame` in the current scope
   --> src/lib.rs:549:27
    |
549 |             lf: (*ptr).df.lazy(), 
    |                           ^^^^ method not found in `polars::prelude::DataFrame`

任何有关确定正确库的指导将不胜感激！

Answer 1

Dataframe::lazy该功能后面是否标记了lazy功能

尝试将您的cargo.toml从更改 polars = "0.22.1" 为 polars = {version = "0.22.1", features = ["lazy"]}