Re: [Mesa-dev] [PATCH 21/26] python: Use key-functions when sorting containers

[Eric Engestrom]

On Thursday, 2018-07-05 09:38:19 -0700, Dylan Baker wrote:
> Quoting Mathieu Bridon (2018-07-05 06:17:52)
> > In Python 2, the traditional way to sort containers was to use a
> > comparison function (which returned either -1, 0 or 1 when passed two
> > objects) and pass that as the "cmp" argument to the container's sort()
> > method.
> > 
> > Python 2.4 introduced key-functions, which instead only operate on a
> > given item, and return a sorting key for this item.
> > 
> > In general, this runs faster, because the cmp-function has to get run
> > multiple times for each item of the container.
> > 
> > Python 3 removed the cmp-function, enforcing usage of key-functions
> > instead.
> > 
> > This change makes the script compatible with Python 2 and Python 3.
> > 
> > Signed-off-by: Mathieu Bridon 
> > ---
> >  src/mapi/mapi_abi.py | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/mapi/mapi_abi.py b/src/mapi/mapi_abi.py
> > index 67fdb10650..19fdc4572a 100644
> > --- a/src/mapi/mapi_abi.py
> > +++ b/src/mapi/mapi_abi.py
> > @@ -32,6 +32,7 @@ import os
> >  GLAPI = os.path.join(".", os.path.dirname(sys.argv[0]), "glapi/gen")
> >  sys.path.append(GLAPI)
> >  
> > +from operator import attrgetter
> >  import re
> >  from optparse import OptionParser
> >  import gl_XML
> > @@ -305,7 +306,7 @@ class ABIPrinter(object):
> >  
> >  # sort entries by their names
> >  self.entries_sorted_by_names = self.entries[:]
> > -self.entries_sorted_by_names.sort(lambda x, y: cmp(x.name, y.name))
> > +self.entries_sorted_by_names.sort(key=attrgetter('name'))
> 
> how about:
> self.entries_sorted_by_names = list(sorted(self.entries, 
> key=attrgetter('name')))
> 
> To avoid the copy and in-place sort.

Good idea; with that:
Reviewed-by: Eric Engestrom 

> 
> >  
> >  self.indent = ' ' * 3
> >  self.noop_warn = 'noop_warn'
> > @@ -455,7 +456,7 @@ class ABIPrinter(object):
> >  """Return the string pool for use by stubs."""
> >  # sort entries by their names
> >  sorted_entries = self.entries[:]
> > -sorted_entries.sort(lambda x, y: cmp(x.name, y.name))
> > +sorted_entries.sort(key=attrgetter('name'))
> >  
> >  pool = []
> >  offsets = {}
> > -- 
> > 2.17.1
> > 
> > ___
> > mesa-dev mailing list
> > mesa-dev@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
___
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev

Re: [Mesa-dev] [PATCH 21/26] python: Use key-functions when sorting containers

[Dylan Baker]

Quoting Mathieu Bridon (2018-07-05 06:17:52)
> In Python 2, the traditional way to sort containers was to use a
> comparison function (which returned either -1, 0 or 1 when passed two
> objects) and pass that as the "cmp" argument to the container's sort()
> method.
> 
> Python 2.4 introduced key-functions, which instead only operate on a
> given item, and return a sorting key for this item.
> 
> In general, this runs faster, because the cmp-function has to get run
> multiple times for each item of the container.
> 
> Python 3 removed the cmp-function, enforcing usage of key-functions
> instead.
> 
> This change makes the script compatible with Python 2 and Python 3.
> 
> Signed-off-by: Mathieu Bridon 
> ---
>  src/mapi/mapi_abi.py | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/src/mapi/mapi_abi.py b/src/mapi/mapi_abi.py
> index 67fdb10650..19fdc4572a 100644
> --- a/src/mapi/mapi_abi.py
> +++ b/src/mapi/mapi_abi.py
> @@ -32,6 +32,7 @@ import os
>  GLAPI = os.path.join(".", os.path.dirname(sys.argv[0]), "glapi/gen")
>  sys.path.append(GLAPI)
>  
> +from operator import attrgetter
>  import re
>  from optparse import OptionParser
>  import gl_XML
> @@ -305,7 +306,7 @@ class ABIPrinter(object):
>  
>  # sort entries by their names
>  self.entries_sorted_by_names = self.entries[:]
> -self.entries_sorted_by_names.sort(lambda x, y: cmp(x.name, y.name))
> +self.entries_sorted_by_names.sort(key=attrgetter('name'))

how about:
self.entries_sorted_by_names = list(sorted(self.entries, 
key=attrgetter('name')))

To avoid the copy and in-place sort.

>  
>  self.indent = ' ' * 3
>  self.noop_warn = 'noop_warn'
> @@ -455,7 +456,7 @@ class ABIPrinter(object):
>  """Return the string pool for use by stubs."""
>  # sort entries by their names
>  sorted_entries = self.entries[:]
> -sorted_entries.sort(lambda x, y: cmp(x.name, y.name))
> +sorted_entries.sort(key=attrgetter('name'))
>  
>  pool = []
>  offsets = {}
> -- 
> 2.17.1
> 
> ___
> mesa-dev mailing list
> mesa-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev


signature.asc
Description: signature
___
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev

[Mesa-dev] [PATCH 21/26] python: Use key-functions when sorting containers

[Mathieu Bridon]

In Python 2, the traditional way to sort containers was to use a
comparison function (which returned either -1, 0 or 1 when passed two
objects) and pass that as the "cmp" argument to the container's sort()
method.

Python 2.4 introduced key-functions, which instead only operate on a
given item, and return a sorting key for this item.

In general, this runs faster, because the cmp-function has to get run
multiple times for each item of the container.

Python 3 removed the cmp-function, enforcing usage of key-functions
instead.

This change makes the script compatible with Python 2 and Python 3.

Signed-off-by: Mathieu Bridon 
---
 src/mapi/mapi_abi.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/mapi/mapi_abi.py b/src/mapi/mapi_abi.py
index 67fdb10650..19fdc4572a 100644
--- a/src/mapi/mapi_abi.py
+++ b/src/mapi/mapi_abi.py
@@ -32,6 +32,7 @@ import os
 GLAPI = os.path.join(".", os.path.dirname(sys.argv[0]), "glapi/gen")
 sys.path.append(GLAPI)
 
+from operator import attrgetter
 import re
 from optparse import OptionParser
 import gl_XML
@@ -305,7 +306,7 @@ class ABIPrinter(object):
 
 # sort entries by their names
 self.entries_sorted_by_names = self.entries[:]
-self.entries_sorted_by_names.sort(lambda x, y: cmp(x.name, y.name))
+self.entries_sorted_by_names.sort(key=attrgetter('name'))
 
 self.indent = ' ' * 3
 self.noop_warn = 'noop_warn'
@@ -455,7 +456,7 @@ class ABIPrinter(object):
 """Return the string pool for use by stubs."""
 # sort entries by their names
 sorted_entries = self.entries[:]
-sorted_entries.sort(lambda x, y: cmp(x.name, y.name))
+sorted_entries.sort(key=attrgetter('name'))
 
 pool = []
 offsets = {}
-- 
2.17.1

___
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev