series

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 Go to latest Published: Mar 11, 2026 License: MIT Imports: 13 Imported by: 0

Documentation

Overview

Package series provides the Series type, a named typed column of data.

A Series wraps an array with a name and data type, providing a high-level API for column operations. Series are immutable after construction; all mutation operations return new Series values.

All read operations on a Series are safe for concurrent use by multiple goroutines.

Index

Constants

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Variables

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Functions

This section is empty.

Types

type DtAccessor 

type DtAccessor struct {
	// contains filtered or unexported fields
}

DtAccessor provides temporal operations on Date/DateTime/Time/Duration Series.

func (*DtAccessor) Day 

func (a *DtAccessor) Day() *Series

Day returns an Int32 Series with the day of month component.

func (*DtAccessor) DayOfYear 

func (a *DtAccessor) DayOfYear() *Series

DayOfYear returns an Int32 Series with the day of year (1-366).

func (*DtAccessor) Epoch 

func (a *DtAccessor) Epoch(unit string) *Series

Epoch returns an Int64 Series with the epoch value in the given time unit. Supported units: "s" (seconds), "ms" (milliseconds), "us" (microseconds), "ns" (nanoseconds).

func (*DtAccessor) Hour 

func (a *DtAccessor) Hour() *Series

Hour returns an Int32 Series with the hour component.

func (*DtAccessor) IsoWeek 

func (a *DtAccessor) IsoWeek() *Series

IsoWeek returns an Int32 Series with the ISO week number.

func (*DtAccessor) Minute 

func (a *DtAccessor) Minute() *Series

Minute returns an Int32 Series with the minute component.

func (*DtAccessor) Month 

func (a *DtAccessor) Month() *Series

Month returns an Int32 Series with the month component (1-12).

func (*DtAccessor) Nanosecond 

func (a *DtAccessor) Nanosecond() *Series

Nanosecond returns an Int32 Series with the nanosecond component.

func (*DtAccessor) OffsetBy 

func (a *DtAccessor) OffsetBy(duration string) *Series

OffsetBy offsets temporal values by a duration string. Supported formats: "1d", "2mo", "-1y", "3h", etc.

func (*DtAccessor) Quarter 

func (a *DtAccessor) Quarter() *Series

Quarter returns an Int32 Series with the quarter (1-4).

func (*DtAccessor) Second 

func (a *DtAccessor) Second() *Series

Second returns an Int32 Series with the second component.

func (*DtAccessor) Strftime 

func (a *DtAccessor) Strftime(format string) *Series

Strftime formats temporal values using a Go time format string.

func (*DtAccessor) TotalSeconds 

func (a *DtAccessor) TotalSeconds() *Series

TotalSeconds returns a Float64 Series with the total duration in seconds. Only applicable to Duration series (microseconds).

func (*DtAccessor) Truncate 

func (a *DtAccessor) Truncate(unit string) *Series

Truncate truncates temporal values to the given unit. Supported units: "1h", "1d", "1mo", "1y"

func (*DtAccessor) Weekday 

func (a *DtAccessor) Weekday() *Series

Weekday returns an Int32 Series with the weekday (0=Sunday, 6=Saturday).

func (*DtAccessor) Year 

func (a *DtAccessor) Year() *Series

Year returns an Int32 Series with the year component.

type Series 

type Series struct {
	// contains filtered or unexported fields
}

Series is a named, typed column of data. It wraps an underlying columnar array with a name and provides a rich API for data manipulation.

func New 

func New(name string, arr array.Array) *Series

New creates a new Series with the given name and underlying array.

func NewBoolean 

func NewBoolean(name string, data []bool) *Series

NewBoolean creates a new Series of boolean values.

func NewBooleanWithValidity 

func NewBooleanWithValidity(name string, data []bool, valid []bool) *Series

NewBooleanWithValidity creates a Boolean Series with explicit null tracking.

func NewDate 

func NewDate(name string, data []int32) *Series

NewDate creates a new Series of Date values (days since Unix epoch as int32).

func NewDateTime 

func NewDateTime(name string, data []int64) *Series

NewDateTime creates a new Series of DateTime values (microseconds since epoch as int64).

func NewDateTimeWithValidity 

func NewDateTimeWithValidity(name string, data []int64, valid []bool) *Series

NewDateTimeWithValidity creates a DateTime Series with explicit null tracking.

func NewDateWithValidity 

func NewDateWithValidity(name string, data []int32, valid []bool) *Series

NewDateWithValidity creates a Date Series with explicit null tracking.

func NewDuration 

func NewDuration(name string, data []int64) *Series

NewDuration creates a new Series of Duration values (microseconds as int64).

func NewDurationWithValidity 

func NewDurationWithValidity(name string, data []int64, valid []bool) *Series

NewDurationWithValidity creates a Duration Series with explicit null tracking.

func NewFloat32 

func NewFloat32(name string, data []float32) *Series

NewFloat32 creates a new Series of float32 values.

func NewFloat64 

func NewFloat64(name string, data []float64) *Series

NewFloat64 creates a new Series of float64 values.

func NewFloat64WithValidity 

func NewFloat64WithValidity(name string, data []float64, valid []bool) *Series

NewFloat64WithValidity creates a Float64 Series with explicit null tracking.

func NewInt8 

func NewInt8(name string, data []int8) *Series

NewInt8 creates a new Series of int8 values.

func NewInt16 

func NewInt16(name string, data []int16) *Series

NewInt16 creates a new Series of int16 values.

func NewInt32 

func NewInt32(name string, data []int32) *Series

NewInt32 creates a new Series of int32 values.

func NewInt32WithValidity 

func NewInt32WithValidity(name string, data []int32, valid []bool) *Series

NewInt32WithValidity creates an Int32 Series with explicit null tracking.

func NewInt64 

func NewInt64(name string, data []int64) *Series

NewInt64 creates a new Series of int64 values.

func NewInt64WithValidity 

func NewInt64WithValidity(name string, data []int64, valid []bool) *Series

NewInt64WithValidity creates an Int64 Series with explicit null tracking. Positions where valid[i] is false are marked as null.

func NewString 

func NewString(name string, data []string) *Series

NewString creates a new Series of string values.

func NewStringWithValidity 

func NewStringWithValidity(name string, data []string, valid []bool) *Series

NewStringWithValidity creates a String Series with explicit null tracking.

func NewTime 

func NewTime(name string, data []int64) *Series

NewTime creates a new Series of Time values (nanoseconds since midnight as int64).

func NewTimeWithValidity 

func NewTimeWithValidity(name string, data []int64, valid []bool) *Series

NewTimeWithValidity creates a Time Series with explicit null tracking.

func NewUInt8 

func NewUInt8(name string, data []uint8) *Series

NewUInt8 creates a new Series of uint8 values.

func NewUInt16 

func NewUInt16(name string, data []uint16) *Series

NewUInt16 creates a new Series of uint16 values.

func NewUInt32 

func NewUInt32(name string, data []uint32) *Series

NewUInt32 creates a new Series of uint32 values.

func NewUInt64 

func NewUInt64(name string, data []uint64) *Series

NewUInt64 creates a new Series of uint64 values.

func (*Series) ArgMax 

func (s *Series) ArgMax() (int, bool)

ArgMax returns the index of the maximum non-null value. Returns -1, false if the series is empty or all null.

func (*Series) ArgMin 

func (s *Series) ArgMin() (int, bool)

ArgMin returns the index of the minimum non-null value. Returns -1, false if the series is empty or all null.

func (*Series) ArgSort 

func (s *Series) ArgSort(descending bool) []int

ArgSort returns the indices that would sort this Series. Nulls are placed at the end.

func (*Series) Array 

func (s *Series) Array() array.Array

Array returns the underlying array storage.

func (*Series) BooleanArray 

func (s *Series) BooleanArray() *array.BooleanArray

BooleanArray returns the underlying BooleanArray, or nil if wrong type.

func (*Series) Cast 

func (s *Series) Cast(target dtype.DataType) (*Series, error)

Cast converts the Series to the target data type. Supported casts:

  • Int64 <-> Float64 (numeric conversion)
  • Int64/Float64 -> String (formatting)
  • String -> Int64/Float64 (parsing, invalid values become null)
  • Boolean -> Int64 (true=1, false=0)
  • Int64 -> Boolean (0=false, nonzero=true)

func (*Series) Count 

func (s *Series) Count() int

Count returns the number of non-null values.

func (*Series) CumMax 

func (s *Series) CumMax() *Series

CumMax returns a new Series with the cumulative maximum. Only supports Int64 and Float64 types. Other types return nil.

func (*Series) CumMin 

func (s *Series) CumMin() *Series

CumMin returns a new Series with the cumulative minimum. Only supports Int64 and Float64 types. Other types return nil.

func (*Series) CumProd 

func (s *Series) CumProd() *Series

CumProd returns a new Series with the cumulative product. Only supports Int64 and Float64 types. Other types return nil.

func (*Series) CumSum 

func (s *Series) CumSum() *Series

CumSum returns a new Series with the cumulative sum. Only supports Int64 and Float64 types. Other types return nil.

func (*Series) DataType 

func (s *Series) DataType() dtype.DataType

DataType returns the data type of the series.

func (*Series) Describe 

func (s *Series) Describe() string

Describe returns a summary string with count, mean, std, min, max.

func (*Series) Diff 

func (s *Series) Diff(n int) *Series

Diff returns a new Series with the difference between each element and the element n positions before it. The first n values will be null. Only supports Int64 and Float64 types.

func (*Series) DropNulls 

func (s *Series) DropNulls() *Series

DropNulls returns a new Series with null values removed.

func (*Series) Dt 

func (s *Series) Dt() *DtAccessor

Dt returns a DtAccessor for temporal operations. Returns nil if the Series is not of a temporal type (Date, DateTime, Time, Duration).

func (*Series) Equal 

func (s *Series) Equal(other *Series) bool

Equal checks if two series have the same name, type, length, and values.

func (*Series) FillNullFloat64 

func (s *Series) FillNullFloat64(fillValue float64) *Series

FillNullFloat64 returns a new Float64 Series with nulls replaced by the given value.

func (*Series) FillNullInt64 

func (s *Series) FillNullInt64(fillValue int64) *Series

FillNullInt64 returns a new Int64 Series with nulls replaced by the given value.

func (*Series) FillNullString 

func (s *Series) FillNullString(fillValue string) *Series

FillNullString returns a new String Series with nulls replaced by the given value.

func (*Series) Filter 

func (s *Series) Filter(mask *bitmap.Bitmap) *Series

Filter returns a new Series containing only elements where mask bits are set.

func (*Series) Float64Values 

func (s *Series) Float64Values() []float64

Float64Values returns the underlying float64 slice, or nil if wrong type.

func (*Series) GetBool 

func (s *Series) GetBool(i int) (bool, bool)

GetBool returns the boolean value at index i and whether it's valid.

func (*Series) GetFloat64 

func (s *Series) GetFloat64(i int) (float64, bool)

GetFloat64 returns the float64 value at index i and whether it's valid.

func (*Series) GetInt32 

func (s *Series) GetInt32(i int) (int32, bool)

GetInt32 returns the int32 value at index i and whether it's valid.

func (*Series) GetInt64 

func (s *Series) GetInt64(i int) (int64, bool)

GetInt64 returns the int64 value at index i and whether it's valid.

func (*Series) GetString 

func (s *Series) GetString(i int) (string, bool)

GetString returns the string value at index i and whether it's valid.

func (*Series) HasNulls 

func (s *Series) HasNulls() bool

HasNulls returns true if the series contains any null values.

func (*Series) Head 

func (s *Series) Head(n int) *Series

Head returns the first n elements.

func (*Series) Int64Values 

func (s *Series) Int64Values() []int64

Int64Values returns the underlying int64 slice, or nil if wrong type.

func (*Series) Interpolate 

func (s *Series) Interpolate(method string) *Series

Interpolate fills null values using the specified method. Supported methods: "linear", "pad"/"ffill" (forward fill), "bfill" (backward fill). Only works for numeric types. The "linear" method always returns Float64.

func (*Series) IsDuplicated 

func (s *Series) IsDuplicated() *Series

IsDuplicated returns a Boolean Series where true indicates the value at that position appears more than once in the Series.

func (*Series) IsNotNullSeries 

func (s *Series) IsNotNullSeries() *Series

IsNotNullSeries returns a Boolean Series where true indicates a non-null in the original.

func (*Series) IsNull 

func (s *Series) IsNull(i int) bool

IsNull returns true if the element at index i is null.

func (*Series) IsNullSeries 

func (s *Series) IsNullSeries() *Series

IsNullSeries returns a Boolean Series where true indicates a null in the original.

func (*Series) IsValid 

func (s *Series) IsValid(i int) bool

IsValid returns true if the element at index i is not null.

func (*Series) Len 

func (s *Series) Len() int

Len returns the number of elements in the series.

func (*Series) Max 

func (s *Series) Max() (float64, bool)

Max returns the maximum non-null value as a float64. The second return value is false if the series is empty or all null.

func (*Series) Mean 

func (s *Series) Mean() (float64, bool)

Mean returns the arithmetic mean of all non-null values. The second return value is false if the series is empty or all null.

func (*Series) Min 

func (s *Series) Min() (float64, bool)

Min returns the minimum non-null value as a float64. The second return value is false if the series is empty or all null.

func (*Series) NUnique 

func (s *Series) NUnique() int

NUnique returns the number of unique non-null values. This is an O(n) operation that uses a hash set internally.

func (*Series) Name 

func (s *Series) Name() string

Name returns the name of the series.

func (*Series) NullCount 

func (s *Series) NullCount() int

NullCount returns the number of null elements.

func (*Series) PctChange 

func (s *Series) PctChange(n int) *Series

PctChange returns the percentage change between each element and the element n positions before it. Results are Float64. The first n values will be null.

func (*Series) Rank 

func (s *Series) Rank(method string) *Series

Rank assigns ranks to the values in the series. Supported methods: "average", "min", "max", "dense", "ordinal". Null values receive null in the output.

func (*Series) Rename 

func (s *Series) Rename(name string) *Series

Rename returns a new Series with the given name.

func (*Series) RollingMax 

func (s *Series) RollingMax(window int) *Series

RollingMax computes the rolling maximum with the given window size. Returns a Float64 Series. The first (window-1) values are null.

func (*Series) RollingMean 

func (s *Series) RollingMean(window int) *Series

RollingMean computes the rolling mean with the given window size. Returns a Float64 Series. The first (window-1) values are null.

func (*Series) RollingMin 

func (s *Series) RollingMin(window int) *Series

RollingMin computes the rolling minimum with the given window size. Returns a Float64 Series. The first (window-1) values are null.

func (*Series) RollingStd 

func (s *Series) RollingStd(window int) *Series

RollingStd computes the rolling standard deviation with the given window size. Returns a Float64 Series. The first (window-1) values are null.

func (*Series) RollingSum 

func (s *Series) RollingSum(window int) *Series

RollingSum computes the rolling sum with the given window size. Returns a Float64 Series. The first (window-1) values are null.

func (*Series) Shift 

func (s *Series) Shift(n int) *Series

Shift returns a new Series with values shifted by n positions. Positive n shifts down (introduces nulls at the top). Negative n shifts up (introduces nulls at the bottom).

func (*Series) Slice 

func (s *Series) Slice(start, end int) *Series

Slice returns a new Series for the range [start, end).

func (*Series) Sort 

func (s *Series) Sort(descending bool) *Series

Sort returns a new Series with elements sorted. Nulls are placed at the end.

func (*Series) Std 

func (s *Series) Std() (float64, bool)

Std returns the standard deviation of all non-null values. Uses ddof=1 (sample standard deviation) by default.

func (*Series) StdDDOF 

func (s *Series) StdDDOF(ddof int) (float64, bool)

StdDDOF returns the standard deviation with the specified delta degrees of freedom.

func (*Series) Str 

func (s *Series) Str() *StrAccessor

Str returns a StrAccessor for string operations. Returns nil if the Series is not of String type.

func (*Series) String 

func (s *Series) String() string

String returns a human-readable representation of the series.

func (*Series) StringArray 

func (s *Series) StringArray() *array.StringArray

StringArray returns the underlying StringArray, or nil if wrong type.

func (*Series) Sum 

func (s *Series) Sum() (float64, bool)

Sum returns the sum of all non-null values as a float64. The second return value is false if the series is empty or all null.

func (*Series) Tail 

func (s *Series) Tail(n int) *Series

Tail returns the last n elements.

func (*Series) Take 

func (s *Series) Take(indices []int) *Series

Take returns a new Series with elements at the given indices.

func (*Series) TryCast 

func (s *Series) TryCast(target dtype.DataType) *Series

TryCast attempts to cast the series to the target type, returning null on failure instead of an error. This is a permissive version of Cast.

func (*Series) Unique 

func (s *Series) Unique() *Series

Unique returns a new Series containing only unique values. Order is preserved (first occurrence is kept). Null appears at most once in the result.

func (*Series) Validity 

func (s *Series) Validity() *bitmap.Bitmap

Validity returns the null bitmap, or nil if there are no nulls.

func (*Series) Var 

func (s *Series) Var() (float64, bool)

Var returns the variance of all non-null values. Uses ddof=1 (sample variance) by default.

func (*Series) VarDDOF 

func (s *Series) VarDDOF(ddof int) (float64, bool)

VarDDOF returns the variance with the specified delta degrees of freedom.

type StrAccessor 

type StrAccessor struct {
	// contains filtered or unexported fields
}

StrAccessor provides string operations on a String Series.

func (*StrAccessor) Capitalize 

func (a *StrAccessor) Capitalize() *Series

Capitalize returns a new String Series with the first character of each string uppercased and the rest lowercased.

func (*StrAccessor) Contains 

func (a *StrAccessor) Contains(substr string) *Series

Contains returns a Boolean Series indicating whether each string contains substr.

func (*StrAccessor) CountMatches 

func (a *StrAccessor) CountMatches(pattern string) *Series

CountMatches counts the number of non-overlapping matches of a regex pattern.

func (*StrAccessor) EndsWith 

func (a *StrAccessor) EndsWith(suffix string) *Series

EndsWith returns a Boolean Series indicating whether each string ends with suffix.

func (*StrAccessor) Extract 

func (a *StrAccessor) Extract(pattern string, groupIndex int) *Series

Extract extracts the first match of a regex pattern, returning the given group. groupIndex 0 returns the full match; 1+ return capture groups.

func (*StrAccessor) Lengths 

func (a *StrAccessor) Lengths() *Series

Lengths returns an Int64 Series with the length (in runes) of each string.

func (*StrAccessor) Pad 

func (a *StrAccessor) Pad(width int, side string, fillChar rune) *Series

Pad pads each string to the given width with fillChar. side must be "left", "right", or "both".

func (*StrAccessor) Replace 

func (a *StrAccessor) Replace(old, new string) *Series

Replace replaces all occurrences of old with new in each string.

func (*StrAccessor) Slice 

func (a *StrAccessor) Slice(start, length int) *Series

Slice extracts a substring from each string using start and length.

func (*StrAccessor) Split 

func (a *StrAccessor) Split(sep string, index int) *Series

Split splits each string by the separator and returns a new String Series containing the nth element (0-indexed). If the index is out of range, the value is null.

func (*StrAccessor) StartsWith 

func (a *StrAccessor) StartsWith(prefix string) *Series

StartsWith returns a Boolean Series indicating whether each string starts with prefix.

func (*StrAccessor) Strip 

func (a *StrAccessor) Strip(chars string) *Series

Strip removes the given characters from both ends of each string.

func (*StrAccessor) ToDatetime 

func (a *StrAccessor) ToDatetime(layout string) *Series

ToDatetime parses each string into a DateTime Series using the given Go time layout. Returns a DateTime Series (microseconds since epoch). Unparseable values become null.

func (*StrAccessor) ToLower 

func (a *StrAccessor) ToLower() *Series

ToLower returns a new String Series with all characters lowercased.

func (*StrAccessor) ToUpper 

func (a *StrAccessor) ToUpper() *Series

ToUpper returns a new String Series with all characters uppercased.

func (*StrAccessor) Trim 

func (a *StrAccessor) Trim() *Series

Trim removes leading and trailing whitespace from each string.

func (*StrAccessor) ZFill 

func (a *StrAccessor) ZFill(width int) *Series

ZFill pads each string on the left with '0' to the given width.

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