Expression

FieldExpression

ScalarExpression

ComparisonExpression

InExpression

AndExpression

OrExpression

NotExpression

IsValidExpression

<code>Expression</code>s are used to define filter logic for passing to a <a rd-options="" href="/link/Dataset?package=arrow&version=0.16.0.2" data-mini-rdoc="arrow::Dataset">Dataset</a>
<a rd-options="" href="/link/Scanner?package=arrow&version=0.16.0.2" data-mini-rdoc="arrow::Scanner">Scanner</a>. <code>FieldExpression</code>s refer to columns in the <code>Dataset</code> and are
compared to <code>ScalarExpression</code>s using <code>ComparisonExpression</code>s.
<code>ComparisonExpression</code>s may be combined with <code>AndExpression</code> or
<code>OrExpression</code> and negated with <code>NotExpression</code>. <code>IsValidExpression</code> is
essentially <code>is.na()</code> for <code>Expression</code>s.

'Apache' 'Arrow' <https://arrow.apache.org/> is a cross-language
development platform for in-memory data. It specifies a standardized
language-independent columnar memory format for flat and hierarchical data,
organized for efficient analytic operations on modern hardware. This
package provides an interface to the 'Arrow C++' library.

Neal Richardson

arrow

Integration to 'Apache' 'Arrow'

Romain François

Jeroen Ooms

Javier Luraschi

Jeffrey Wong

Apache Arrow 

Expression function

<code>FieldExpression$create(name)</code> takes a string name as input. This string should
refer to a column in a <code>Dataset</code> at the time it is evaluated, but you can
construct a <code>FieldExpression</code> independently of any <code>Dataset</code>.<code>ScalarExpression$create(x)</code> takes a scalar (length-1) R value as input.<code>ComparisonExpression$create(OP, e1, e2)</code> takes a string operator name
(e.g. "==", "!=", "&gt;", etc.) and two <code>Expression</code> objects.<code>AndExpression$create(e1, e2)</code> and <code>OrExpression$create(e1, e2)</code> take
two <code>Expression</code> objects, while <code>NotExpression$create(e1)</code> and
<code>IsValidExpression$create(e1)</code> take a single <code>Expression</code>.

Factory

<code>Expression</code>s are used to define filter logic for passing to a <a rd-options='' href='Dataset'>Dataset</a>
<a rd-options='' href='Scanner'>Scanner</a>. <code>FieldExpression</code>s refer to columns in the <code>Dataset</code> and are
compared to <code>ScalarExpression</code>s using <code>ComparisonExpression</code>s.
<code>ComparisonExpression</code>s may be combined with <code>AndExpression</code> or
<code>OrExpression</code> and negated with <code>NotExpression</code>. <code>IsValidExpression</code> is
essentially <code>is.na()</code> for <code>Expression</code>s.

Arrow expressions — Expression

Arrow expressions

Expression: Arrow expressions

Description

Arguments

Factory