Struct polars::prelude::JsonWriter

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pub struct JsonWriter<W>
where W: Write,
{ /* private fields */ }
Available on crate feature polars-io only.
Expand description

Writes a DataFrame to JSON.

Under the hood, this uses arrow2::io::json. arrow2 generally serializes types that are not JSON primitives, such as Date and DateTime, as their Display-formatted versions. For instance, a (naive) DateTime column is formatted as the String "yyyy-mm-dd HH:MM:SS". To control how non-primitive columns are serialized, convert them to String or another primitive type before serializing.

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impl<W> JsonWriter<W>
where W: Write,

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pub fn with_json_format(self, format: JsonFormat) -> JsonWriter<W>

Trait Implementations§

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impl<W> SerWriter<W> for JsonWriter<W>
where W: Write,

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fn new(buffer: W) -> JsonWriter<W>

Create a new JsonWriter writing to buffer with format JsonFormat::JsonLines. To specify a different format, use e.g., JsonWriter::new(buffer).with_json_format(JsonFormat::Json).

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fn finish(&mut self, df: &mut DataFrame) -> Result<(), PolarsError>

Auto Trait Implementations§

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impl<W> Freeze for JsonWriter<W>
where W: Freeze,

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impl<W> RefUnwindSafe for JsonWriter<W>
where W: RefUnwindSafe,

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impl<W> Send for JsonWriter<W>
where W: Send,

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impl<W> Sync for JsonWriter<W>
where W: Sync,

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impl<W> Unpin for JsonWriter<W>
where W: Unpin,

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impl<W> UnwindSafe for JsonWriter<W>
where W: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V