Maintenance Ruby 3.4 gets fixes, but no new features. Switch to Ruby 4.0 →
class method
ENV.select!
ENV.select! { |name, value| block } → ENV or nil
ENV.select! → an_enumerator
ENV.filter! { |name, value| block } → ENV or nil
ENV.filter! → an_enumerator
hash.c
View on GitHub ↗
static VALUE
env_select_bang(VALUE ehash)
{
VALUE keys;
long i;
int del = 0;
RETURN_SIZED_ENUMERATOR(ehash, 0, 0, rb_env_size);
keys = env_keys(FALSE);
RBASIC_CLEAR_CLASS(keys);
for (i=0; i<RARRAY_LEN(keys); i++) {
VALUE val = rb_f_getenv(Qnil, RARRAY_AREF(keys, i));
if (!NIL_P(val)) {
if (!RTEST(rb_yield_values(2, RARRAY_AREF(keys, i), val))) {
env_delete(RARRAY_AREF(keys, i));
del++;
}
}
}
RB_GC_GUARD(keys);
if (del == 0) return Qnil;
return envtbl;
}
Yields each environment variable name and its value as a 2-element Array, deleting each entry for which the block returns false or nil, and returning ENV if any deletions made, or nil otherwise:
Example
ENV.replace('foo' => '0', 'bar' => '1', 'baz' => '2') ENV.select! { |name, value| name.start_with?('b') } # => ENV ENV # => {"bar"=>"1", "baz"=>"2"} ENV.select! { |name, value| true } # => nil ENV.replace('foo' => '0', 'bar' => '1', 'baz' => '2') ENV.filter! { |name, value| name.start_with?('b') } # => ENV ENV # => {"bar"=>"1", "baz"=>"2"} ENV.filter! { |name, value| true } # => nil
Returns an Enumerator if no block given:
Example
ENV.replace('foo' => '0', 'bar' => '1', 'baz' => '2') e = ENV.select! # => #<Enumerator: {"bar"=>"1", "baz"=>"2"}:select!> e.each { |name, value| name.start_with?('b') } # => ENV ENV # => {"bar"=>"1", "baz"=>"2"} e.each { |name, value| true } # => nil ENV.replace('foo' => '0', 'bar' => '1', 'baz' => '2') e = ENV.filter! # => #<Enumerator: {"bar"=>"1", "baz"=>"2"}:filter!> e.each { |name, value| name.start_with?('b') } # => ENV ENV # => {"bar"=>"1", "baz"=>"2"} e.each { |name, value| true } # => nil