Python Generators: Difference between revisions

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=Overview=
=Overview=
A generator is a way to construct a new [[Python_Iterators#Overview|iterable]] object. Whereas normal functions execute and return a single result at a time, generators can return a sequence of multiple values by pausing and resuming execution each time the generator is used. To create a generator, use the <code>[[Python_Language#yield|yield]]</code> keyword instead of <code>return</code> in a function.
A generator is a way to construct a new [[Python_Iterators#Overview|iterable]] object. Whereas normal functions execute and return a single result at a time, generators can return a sequence of multiple values by pausing and resuming execution each time the generator is used. To create a generator, use the <code>[[Python_Language#yield|yield]]</code> keyword instead of <code>return</code> in a function.
<syntaxhighlight lang='py'>
def squares(n=10):
  for i in range(1, n+1):
    yield i ** 2
</syntaxhighlight>
When the generator is called no code is immediately executed:
<syntaxhighlight lang='py'>
gen = squares()
</syntaxhighlight>
It is not until you request elements from the generator that it begins executing code:
<syntaxhighlight lang='py'>
for x in gen:
  print(x)
</syntaxhighlight>


=Use Cases=
=Use Cases=


Create a [[Python_Language_List#Pass_a_Generator_Expression|list with a generator]].
Create a [[Python_Language_List#Pass_a_Generator_Expression|list with a generator]].

Revision as of 19:05, 17 May 2024

Internal

TODO

  • PROCESS IPy Generators Page 101.
  • PROCESS PyOOP "Generator expressions"
  • PROCESS PyOOP "Generators" + "Yield items from another iterable"

Overview

A generator is a way to construct a new iterable object. Whereas normal functions execute and return a single result at a time, generators can return a sequence of multiple values by pausing and resuming execution each time the generator is used. To create a generator, use the yield keyword instead of return in a function.

def squares(n=10):
  for i in range(1, n+1):
    yield i ** 2

When the generator is called no code is immediately executed:

gen = squares()

It is not until you request elements from the generator that it begins executing code:

for x in gen:
  print(x)

Use Cases

Create a list with a generator.