Struct Histogram 

pub struct Histogram {
    pub buckets: Vec<HistogramBucket>,
    pub total_count: i64,
    pub distinct_count: usize,
    pub null_count: i64,
}

A histogram representing the distribution of values in a column.

Fields

buckets: Vec<HistogramBucket>

The buckets in the histogram, ordered by frequency (descending)

total_count: i64

Total number of values (including nulls if present)

distinct_count: usize

Number of distinct values

null_count: i64

Number of null values

Implementations

impl Histogram

pub fn new( buckets: Vec<HistogramBucket>, total_count: i64, null_count: i64, ) -> Self

Creates a new histogram from buckets.

pub fn most_common_ratio(&self) -> f64

Returns the ratio of the most common value.

pub fn least_common_ratio(&self) -> f64

Returns the ratio of the least common value.

pub fn bucket_count(&self) -> usize

Returns the number of buckets (distinct values).

pub fn top_n(&self, n: usize) -> Vec<(&str, f64)>

Returns the top N most common values and their ratios.

pub fn is_roughly_uniform(&self, threshold: f64) -> bool

Checks if the distribution is roughly uniform (all values have similar frequencies).

A distribution is considered roughly uniform if the ratio between the most common and least common values is less than the threshold (default 1.5).

pub fn get_value_ratio(&self, value: &str) -> Option<f64>

Gets the ratio for a specific value, if it exists in the histogram.

pub fn entropy(&self) -> f64

Returns the entropy of the distribution.

Higher entropy indicates more uniform distribution.

pub fn follows_power_law(&self, top_n: usize, threshold: f64) -> bool

Checks if the distribution follows a power law (few values dominate).

Returns true if the top n values account for more than threshold of the distribution.

pub fn null_ratio(&self) -> f64

Returns the null ratio in the data.

Trait Implementations

impl Clone for Histogram

fn clone(&self) -> Histogram

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Histogram

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.