4 ms·

Yep. `yield` in Ruby is a normal anonymous method call. It pushes a new frame onto the stack. `yield` in Python works more like Ruby's [Generator](http://ruby-d

Yep. `yield` in Ruby is a normal anonymous method call. It pushes a new frame onto the stack. `yield` in Python works more like Ruby's [Generator](http://ruby-doc.org/stdlib/libdoc/generator/rdoc/classes/Generator.html http://ruby-doc.org/stdlib/libdoc/generator/rdoc/classes/Gen...). It freezes the current stack frame's state and resumes execution somewhere else, returning again to the same place on the next iteration. They're very different things really. More about Python's generators here: http://www.python.org/dev/peps/pep-0255/ http://www.python.org/dev/peps/pep-0255/

AdamN 17y ago
So what would yield in Ruby be like in Python? Surely there must be some analogue?
- rtomayko 17y ago
  You can pass an anonymous function or lambda: def foo(thing, block): thing = "cruel " + thing block(thing) # like `yield thing' or 'block.call' in ruby def bar(thing): return "hello " + thing foo('world', bar) # or: foo('world', lambda x: "hello " + x) Ruby's blocks are really just sugar for passing an anonymous function in the last argument and yield is just sugar for calling that function. The example above in Ruby would be: def foo(thing) yield thing end foo('world') { |thing| "hello " + thing }
- jamesnvc1 17y ago
  Ruby's yield is essentially just calling an anonymous function given to it in the form of a block. e.g., the following code snippets are equivalent Ruby: def foo(bar) if block_given? yield bar end end foo 5 { |x| puts x } # prints 5 Python: def foo(bar,fcn): fcn(bar) foo(5, lambda x: sys.stdout.write("%d\n" % x)) The only real difference being that the ruby code is calling a block versus a "real" function. edit Oops, had this page open for a while, didn't realize someone had replied in the interim, making my response somewhat redundant

AdamN 17y ago

So what would yield in Ruby be like in Python? Surely there must be some analogue?

rtomayko 17y ago
You can pass an anonymous function or lambda: def foo(thing, block): thing = "cruel " + thing block(thing) # like `yield thing' or 'block.call' in ruby def bar(thing): return "hello " + thing foo('world', bar) # or: foo('world', lambda x: "hello " + x) Ruby's blocks are really just sugar for passing an anonymous function in the last argument and yield is just sugar for calling that function. The example above in Ruby would be: def foo(thing) yield thing end foo('world') { |thing| "hello " + thing }
jamesnvc1 17y ago
Ruby's yield is essentially just calling an anonymous function given to it in the form of a block. e.g., the following code snippets are equivalent Ruby: def foo(bar) if block_given? yield bar end end foo 5 { |x| puts x } # prints 5 Python: def foo(bar,fcn): fcn(bar) foo(5, lambda x: sys.stdout.write("%d\n" % x)) The only real difference being that the ruby code is calling a block versus a "real" function. edit Oops, had this page open for a while, didn't realize someone had replied in the interim, making my response somewhat redundant