Questions tagged [rust-polars]
271 questions
1
vote
1 answer
rust polars convert string column to datetime
I'm trying to learn rust and using polars. I've a simple CSV file
names,pdate,orders
alice,2023-02-12,2
alice,2023-02-18,1
alice,2023-02-22,6
bob,2022-12-10,1
bob,2022-12-14,1
bob,2022-12-30,4
I read it in using
let mut df =…
broccoli
- 4,738
- 10
- 42
- 54
1
vote
1 answer
Add a new Date column based off an existing Date column in rust polars
I am trying to add a new column in my polars DataFrame: 'for_date'
There is already a column named 'made_on', and I want 'for_date' to be 1 day greater than 'made_on'. So if 'made_on' is 2022-12-25 then for_date should be 2022-12-26 etc.
My df looks…
kykyi
- 375
- 4
- 10
1
vote
1 answer
Fast way to concatenate two string columns in Rust Polars?
I am currently concatenating two series in Polars like this:
df.with_column(Series::new(
"C",
&(df.column("A").unwrap()
+ &Series::new("", (0..df.shape().0).map(|_| "_").collect::>()))
+…
Jage
- 453
- 2
- 9
1
vote
2 answers
Is it possible to subtract a list column?
I want to operate this expression with data.
But it gives the error that List(float64) type doesn't have the operation.
I guess the list type isn't implemented element-wise operations.
(col("vec").last() - col("vec")).abs().sum()
vec
…
Seongsu Park
- 11
- 1
1
vote
1 answer
how to change datetime series to date series?
let datetime = frame.column("datetime_nano")?.cast(&DataType::Datetime(TimeUnit::Nanoseconds, None))?;
let date = datetime.cast(&DataType::Date)?;
let time = datetime.cast(&DataType::Time)?;
println!("{}", datetime);
println!("{}", date);
The date…
somewheve
- 125
- 6
1
vote
0 answers
How do I convert a Polars DataFrame to Vec?
edit: To hopefully be more concise, how do I do this?-
use polars::prelude::{DataFrame, NamedFrom, df};
use arrow::record_batch::RecordBatch;
fn main() {
let polars_df: DataFrame = df!("cat_data" => &[1.0, 2.0, 3.0, 4.0],
…
user21083829
- 11
- 2
1
vote
1 answer
Rust-polars: how can I pass the "other" parameter for the function "is_in" by reference?
I am very new to Rust so please excuse me if this is a trivial question.
I am trying to filter a dataframe as follows:
let allowed = Series::from_iter(vec![
"string1".to_string(),
"string2".to_string(),
]);
let df =…
101001000100001
- 23
- 4
1
vote
1 answer
How do I read multiple CSV/Parquet/JSON etc files from a directory using Rust?
I am using polars with Rust and I would like to be able to read multiple csv files as input.
I found this section in the documentation that shows how to use glob patterns to read multiple files using Python, but I could not find a way to do this in…
Finlay Weber
- 2,989
- 3
- 17
- 37
1
vote
1 answer
Filter a polars dataframe by date in rust
Im trying to filter a dataframe by date.
But filter it with expressions like this would be really cumbersome for a date like "2019-11-01 10:15:00".
My goal is to do something like the python version:
use polars::export::chrono::NaiveDateTime;
use…
nklsla
- 315
- 1
- 9
1
vote
0 answers
Sending polars Dataframe via juniper GraphQL
I am trying to send the Polars dataframe over juniper GraphQL, but #[juniper::graphql_object] is complaining about trail bound
the trait bound `Result, FieldError>: IntoResolvable<'_, __S, _,…
921kiyo
- 584
- 4
- 14
1
vote
1 answer
Efficient way to update a single element of a Polars DataFrame?
Polars DataFrame does not provide a method to update the value of a single cell currently. Instead, we have to the method DataFrame.apply or DataFrame.apply_at_idx that updates a whole column / Series. This can be very expensive in situations where…
Benjamin Du
- 1,391
- 1
- 17
- 25
1
vote
1 answer
How do I pivot a table using Rust Polars?
How do I create a pivoted dataframe with polars (in Rust), where I can both specify indices and columns?
For indices I want the groups and for the columns I want aggregated calculations per month, and year.
like this, ish:
df = pd.DataFrame({
…
Ynax
- 59
- 4
1
vote
1 answer
Filter by hour of datetime in rust polars
How can I filter a dataframe by the hour of a date column?
let df = df.lazy().select([
col("value").filter(
col("date").dt().hour().gt(7).lt(20)
).alias("hours").sum(),
]).collect()?;
Whith that I get an Error
Error: Invalid operation…
Brucie Alpha
- 1,135
- 2
- 12
- 31
1
vote
2 answers
Compare two Pola-rs dataframes by position
Suppose I have two dataframes like:
let df_1 = df! {
"1" => [1, 2, 2, 3, 4, 3],
"2" => [1, 4, 2, 3, 4, 3],
"3" => [1, 2, 6, 3, 4, 3],
}
.unwrap();
let mut df_2 = df_1.clone();
…
baarkerlounger
- 1,217
- 8
- 40
- 57
1
vote
0 answers
Polars: how to create a dataframe from arrow RecordBatch?
I am using rust arrow library and have a RecordBatch struct. I want to create a Polars dataframe out it, do some operations in the Polars land, and move the result back to RecordBatch. Since both are arrow based, I suppose there might be an…
Nikhil Garg
- 3,944
- 9
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- 37