Compute Functions

Aggregations

count(array, *[, options, memory_pool])	Count the number of null / non-null values.
mean(array, *[, memory_pool])	Compute the mean of a numeric array.
min_max(array, *[, options, memory_pool])	Compute the minimum and maximum values of a numeric array.
mode(array[, n])	Return top-n most common values and number of times they occur in a passed numerical (chunked) array, in descending order of occurance.
stddev(array, *[, options, memory_pool])	Calculate the standard deviation of a numeric array.
sum(array)	Sum the values in a numerical (chunked) array.
variance(array, *[, options, memory_pool])	Calculate the variance of a numeric array.

Arithmetic Functions

By default these functions do not detect overflow. Each function is also available in an overflow-checking variant, suffixed _checked, which throws an ArrowInvalid exception when overflow is detected.

add(x, y, *[, memory_pool])	Add the arguments element-wise.
add_checked(x, y, *[, memory_pool])	Add the arguments element-wise.
divide(dividend, divisor, *[, memory_pool])	Divide the arguments element-wise.
divide_checked(dividend, divisor, *[, …])	Divide the arguments element-wise.
multiply(x, y, *[, memory_pool])	Multiply the arguments element-wise.
multiply_checked(x, y, *[, memory_pool])	Multiply the arguments element-wise.
subtract(x, y, *[, memory_pool])	Substract the arguments element-wise.
subtract_checked(x, y, *[, memory_pool])	Substract the arguments element-wise.

Comparisons

These functions expect two inputs of the same type. If one of the inputs is null they return null.

equal(x, y, *[, memory_pool])	Compare values for equality (x == y).
greater(x, y, *[, memory_pool])	Compare values for ordered inequality (x > y).
greater_equal(x, y, *[, memory_pool])	Compare values for ordered inequality (x >= y).
less(x, y, *[, memory_pool])	Compare values for ordered inequality (x < y).
less_equal(x, y, *[, memory_pool])	Compare values for ordered inequality (x <= y).
not_equal(x, y, *[, memory_pool])	Compare values for inequality (x != y).

Logical Functions

These functions normally emit a null when one of the inputs is null. However, Kleene logic variants are provided (suffixed _kleene). See User Guide for details.

and_(x, y, *[, memory_pool])	Logical ‘and’ boolean values.
and_kleene(x, y, *[, memory_pool])	Logical ‘and’ boolean values (Kleene logic).
all(array, *[, memory_pool])	Test whether all elements in a boolean array evaluate to true..
any(array, *[, memory_pool])	Test whether any element in a boolean array evaluates to true..
invert(values, *[, memory_pool])	Invert boolean values.
or_(x, y, *[, memory_pool])	Logical ‘or’ boolean values.
or_kleene(x, y, *[, memory_pool])	Logical ‘or’ boolean values (Kleene logic).
xor(x, y, *[, memory_pool])	Logical ‘xor’ boolean values.

String Predicates

In these functions an empty string emits false in the output. For ASCII variants (prefixed ascii_) a string element with non-ASCII characters emits false in the output.

The first set of functions emit true if the input contains only characters of a given class.

ascii_is_alnum(strings, *[, memory_pool])	Classify strings as ASCII alphanumeric.
ascii_is_alpha(strings, *[, memory_pool])	Classify strings as ASCII alphabetic.
ascii_is_decimal(strings, *[, memory_pool])	Classify strings as ASCII decimal.
ascii_is_lower(strings, *[, memory_pool])	Classify strings as ASCII lowercase.
ascii_is_printable(strings, *[, memory_pool])	Classify strings as ASCII printable.
ascii_is_space(strings, *[, memory_pool])	Classify strings as ASCII whitespace.
ascii_is_upper(strings, *[, memory_pool])	Classify strings as ASCII uppercase.
utf8_is_alnum(strings, *[, memory_pool])	Classify strings as alphanumeric.
utf8_is_alpha(strings, *[, memory_pool])	Classify strings as alphabetic.
utf8_is_decimal(strings, *[, memory_pool])	Classify strings as decimal.
utf8_is_digit(strings, *[, memory_pool])	Classify strings as digits.
utf8_is_lower(strings, *[, memory_pool])	Classify strings as lowercase.
utf8_is_numeric(strings, *[, memory_pool])	Classify strings as numeric.
utf8_is_printable(strings, *[, memory_pool])	Classify strings as printable.
utf8_is_space(strings, *[, memory_pool])	Classify strings as whitespace.
utf8_is_upper(strings, *[, memory_pool])	Classify strings as uppercase.

The second set of functions also consider the order of characters in the string element.

ascii_is_title(strings, *[, memory_pool])	Classify strings as ASCII titlecase.
utf8_is_title(strings, *[, memory_pool])	Classify strings as titlecase.

The third set of functions examines string elements on a byte-by-byte basis.

string_is_ascii(strings, *[, memory_pool])

Classify strings as ASCII.

String Transforms

ascii_lower(strings, *[, memory_pool])	Transform ASCII input to lowercase.
ascii_upper(strings, *[, memory_pool])	Transform ASCII input to uppercase.
utf8_lower(strings, *[, memory_pool])	Transform input to lowercase.
utf8_upper(strings, *[, memory_pool])	Transform input to uppercase.

Containment tests

index_in(values, *[, options, memory_pool])	Return index of each element in a set of values.
is_in(values, *[, options, memory_pool])	Find each element in a set of values.
match_substring(array, pattern)	Test if substring pattern is contained within a value of a string array.

Conversions

cast(arr, target_type[, safe])	Cast array values to another data type.
strptime(strings, *[, options, memory_pool])	Parse timestamps.

Selections

filter(data, mask[, null_selection_behavior])	Select values (or records) from array- or table-like data given boolean filter, where true values are selected.
take(data, indices, *[, boundscheck, …])	Select values (or records) from array- or table-like data given integer selection indices.

Associative transforms

dictionary_encode(array, *[, memory_pool])	Dictionary-encode array.
unique(array, *[, memory_pool])	Compute unique elements.
value_counts(array, *[, memory_pool])	Compute counts of unique elements.

Sorts and partitions

partition_nth_indices(array, *[, options, …])	Return the indices that would partition an array around a pivot.
sort_indices(input, *[, options, memory_pool])	Return the indices that would sort an array, record batch or table.

Structural Transforms

binary_length(strings, *[, memory_pool])	Compute string lengths.
fill_null(values, fill_value)	Replace each null element in values with fill_value.
is_null(values, *[, memory_pool])	Return true if null.
is_valid(values, *[, memory_pool])	Return true if non-null.
list_value_length(lists, *[, memory_pool])	Compute list lengths.
list_flatten(lists, *[, memory_pool])	Flatten list values.
list_parent_indices(lists, *[, memory_pool])	Compute parent indices of nested list values.