code: def copy_if(
      ary,
      predicate,
      extra_args=None,
      preamble="",
      queue=None,
      wait_for=None,
  ):
      """Copy the elements of *ary* satisfying *predicate* to an output array.
  
      :arg predicate: a C expression evaluating to a ``bool``, represented as a string.
          The value to test is available as ``ary[i]``, and if the expression evaluates
          to ``true``, then this value ends up in the output.
      :arg extra_args: |scan_extra_args|
      :arg preamble: |preamble|
      :arg wait_for: |explain-waitfor|
      :returns: a tuple *(out, count, event)* where *out* is the output array, *count*
          is an on-device scalar (fetch to host with ``count.get()``) indicating
          how many elements satisfied *predicate*, and *event* is a
          :class:`pyopencl.Event` for dependency management. *out* is allocated
          to the same length as *ary*, but only the first *count* entries carry
          meaning.
  
      .. versionadded:: 2013.1
      """
      if len(ary) > np.iinfo(np.int32).max:
          scan_dtype = np.int64
      else:
          scan_dtype = np.int32
  
      if wait_for is None:
          wait_for = []
  
      (
          extra_args_types,
          extra_args_values,
          extra_wait_for,
      ) = _extract_extra_args_types_values(extra_args)
      wait_for = wait_for + extra_wait_for
  
      knl = _copy_if_template.build(
          ary.context,
          type_aliases=(("scan_t", scan_dtype), ("item_t", ary.dtype)),
          var_values=(("predicate", predicate),),
          more_preamble=preamble,
          more_arguments=extra_args_types,
      )
      out = cl.array.empty_like(ary)
      count = ary._new_with_changes(
          data=None, offset=0, shape=(), strides=(), dtype=scan_dtype
      )
  
      evt = knl(
          ary,
          out,
          count,
          *extra_args_values,
          queue=queue,
          wait_for=wait_for,
      )
  
      return out, count, evt
  
imports: from dataclasses import dataclass
  from typing import Optional
  import numpy
  import pyopencl
  import pyopencl.array
  from pyopencl.elementwise import ElementwiseKernel
  from pyopencl.scan import ScanTemplate, GenericScanKernel
  from pyopencl.tools import dtype_to_ctype, get_arg_offset_adjuster_code
  from pytools import memoize, memoize_method
  from mako.template import Template
label_desc: Use image node_id 2 for calling a global function with example usage: copy_if(ary, predicate, extra_args, preamble, queue, wait_for) and returns: out,  count,  evt