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Python IF THEN chain equivalence

P: n/a
I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---
Nov 13 '08 #1
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15 Replies


P: n/a
jzakiya schrieb:
I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---
Of course not. After "do a", it would stop.

You need to use

if x1 < limit:
do a
if x2 < limit:
do b
...
Alternatively, and depending on the nature of "do X", you can do

for x, todo in ((x1, do_a), (x2, do_b), ...):
if x < limit:
todo()
else:
break

This implies though that the "dos" are pure functions without (variable)
arguments.

Diez
Nov 13 '08 #2

P: n/a
I think you should rethink your post. The first case you posted makes no sense in any language I know. Also, a whole lot of nested IF's is a bad idea in any language. In Python, you will end up with code indented 40+ characters if you keep going.

----- Original Message ----
From: jzakiya <jz*****@mail.com>
To: py*********@python.org
Sent: Thursday, November 13, 2008 5:06:53 PM
Subject: Python IF THEN chain equivalence

I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---
--
http://mail.python.org/mailman/listinfo/python-list

__________________________________________________ ________________
Ask a question on any topic and get answers from real people. Go to Yahoo! Answers and share what you know at http://ca.answers.yahoo.com
Nov 13 '08 #3

P: n/a
On Nov 13, 5:21*pm, Alan Baljeu <alanbal...@yahoo.comwrote:
I think you should rethink your post. The first case you posted makes no sense in any language I know. *Also, a whole lot of nested IF's is a bad idea in any language. *In Python, you will end up with code indented 40+ characters if you keep going.

----- Original Message ----
From: jzakiya <jzak...@mail.com>
To: python-l...@python.org
Sent: Thursday, November 13, 2008 5:06:53 PM
Subject: Python IF THEN chain equivalence

I'm translating a program in Python that has this IF Then chain

IF *x1 < limit: * --- do a ---
* * IF *x2 < limit: *--- do b ---
* * * * IF x3 < limit: *--- do c ---
* * * * * * * * * * * *.-----
* * * * * * * * * * * * ------
* * * * * * * * * * IF *x10 < limt: --- do j ---
* * * * * * * * * * THEN
* * * * * * * * *THEN
* * * * * * * -----
* * * * * THEN
* * *THEN
THEN

In other words, as long as * *'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF *x1 < limit:
* * * * --- do a *---
elif x2 < limit:
* * * * --- do b ---
----
----
elif x10 < limit:
* * * *--- do j ---

--http://mail.python.org/mailman/listinfo/python-list

* * * __________________________________________________ ________________
Ask a question on any topic and get answers from real people. Go to Yahoo! Answers and share what you know athttp://ca.answers.yahoo.com

In the code the 'xi's and 'limit' are variables and the --- do letters
---
phrases are simply writes to any array: an_array[xi]=0

Actually, the code makes perfectly good sense, and is a necessity of
the algorithm I'm implementing, and works perfectly good in Forth, and
can be
written quite nicely within a normal page width.

I was just hoping I could perform the equivalent chain in Python
without
having to grossly indent the source code past the normal width of a
printed page.
But if that's the only way to do it in Python, then so be it.
Nov 13 '08 #4

P: n/a
On 2008-11-13, jzakiya <jz*****@mail.comwrote:
I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN
The placement of the THEN statements makes absolutely no sense
in any language I've ever seen.
In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---
No. That's not the same at all.
Here's one solution:

while True:
if x1 limit: break
do a
if x2 limit: break
do b
if x3 limit: break
do c
...
if x10 limit: break
do j
break

--
Grant Edwards grante Yow! Eisenhower!! Your
at mimeograph machine upsets
visi.com my stomach!!
Nov 13 '08 #5

P: n/a
On 2008-11-13, Grant Edwards <invalid@invalidwrote:
On 2008-11-13, jzakiya <jz*****@mail.comwrote:
>I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

The placement of the THEN statements makes absolutely no sense
in any language I've ever seen.
>In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---

No. That's not the same at all.
Here's one solution:

while True:
if x1 limit: break
do a
if x2 limit: break
do b
if x3 limit: break
do c
...
if x10 limit: break
do j
break
Oops. I botched the case where xN == limit. Each of the tests
should be xN >= limit.

--
Grant Edwards grante Yow! ... I see TOILET
at SEATS ...
visi.com
Nov 13 '08 #6

P: n/a
On 2008-11-13 23:31, jzakiya wrote:
On Nov 13, 5:21 pm, Alan Baljeu <alanbal...@yahoo.comwrote:
>I think you should rethink your post. The first case you posted makes no sense in any language I know. Also, a whole lot of nested IF's is a bad idea in any language. In Python, you will end up with code indented 40+ characters if you keep going.

----- Original Message ----
From: jzakiya <jzak...@mail.com>
To: python-l...@python.org
Sent: Thursday, November 13, 2008 5:06:53 PM
Subject: Python IF THEN chain equivalence

I'm translating a program in Python that has this IF Then chain

IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

Is this the equivalence in Python?

IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---

--http://mail.python.org/mailman/listinfo/python-list

__________________________________________________ ________________
Ask a question on any topic and get answers from real people. Go to Yahoo! Answers and share what you know athttp://ca.answers.yahoo.com


In the code the 'xi's and 'limit' are variables and the --- do letters
---
phrases are simply writes to any array: an_array[xi]=0

Actually, the code makes perfectly good sense, and is a necessity of
the algorithm I'm implementing, and works perfectly good in Forth, and
can be
written quite nicely within a normal page width.

I was just hoping I could perform the equivalent chain in Python
without
having to grossly indent the source code past the normal width of a
printed page.
But if that's the only way to do it in Python, then so be it.
You should probably consider using a function and then
convert the conditions to define return points:

def do_something(...args...):

if x1 >= limit:
return
...do a...
if x2 >= limit:
return
...do b...
etc.

That is provided I understand the flow of control in your
example... it's kind of strange to have THEN mark the *end*
of the then-branch in an if-then-else construct.

--
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source (#1, Nov 13 2008)
>>Python/Zope Consulting and Support ... http://www.egenix.com/
mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/
mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/
__________________________________________________ ______________________
2008-11-12: Released mxODBC Connect 0.9.3 http://python.egenix.com/

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::
eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
Registered at Amtsgericht Duesseldorf: HRB 46611
Nov 13 '08 #7

P: n/a
On Nov 13, 5:48*pm, "M.-A. Lemburg" <m...@egenix.comwrote:
On 2008-11-13 23:31, jzakiya wrote:
On Nov 13, 5:21 pm, Alan Baljeu <alanbal...@yahoo.comwrote:
I think you should rethink your post. The first case you posted makes no sense in any language I know. *Also, a whole lot of nested IF's is a bad idea in any language. *In Python, you will end up with code indented 40+ characters if you keep going.
----- Original Message ----
From: jzakiya <jzak...@mail.com>
To: python-l...@python.org
Sent: Thursday, November 13, 2008 5:06:53 PM
Subject: Python IF THEN chain equivalence
I'm translating a program in Python that has this IF Then chain
IF *x1 < limit: * --- do a ---
* * IF *x2 < limit: *--- do b ---
* * * * IF x3 < limit: *--- do c ---
* * * * * * * * * * * *.-----
* * * * * * * * * * * * ------
* * * * * * * * * * IF *x10 < limt: --- do j ---
* * * * * * * * * * THEN
* * * * * * * * *THEN
* * * * * * * -----
* * * * * THEN
* * *THEN
THEN
In other words, as long as * *'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.
Is this the equivalence in Python?
IF *x1 < limit:
* * * * --- do a *---
elif x2 < limit:
* * * * --- do b ---
----
----
elif x10 < limit:
* * * *--- do j ---
--http://mail.python.org/mailman/listinfo/python-list
* * * __________________________________________________ ________________
Ask a question on any topic and get answers from real people. Go to Yahoo! Answers and share what you know athttp://ca.answers.yahoo.com
In the code the 'xi's and 'limit' are variables and the --- do letters
---
phrases are simply writes to any array: * an_array[xi]=0
Actually, the code makes perfectly good sense, and is a necessity of
the algorithm I'm implementing, and works perfectly good in Forth, and
can be
written quite nicely within a normal page width.
I was just hoping I could perform the equivalent chain in Python
without
having to grossly indent the source code past the normal width of a
printed page.
But if that's the only way to do it in Python, then so be it.

You should probably consider using a function and then
convert the conditions to define return points:

def do_something(...args...):

* * if x1 >= limit:
* * * * return
* * ...do a...
* * if x2 >= limit:
* * * * return
* * ...do b...
* * etc.

That is provided I understand the flow of control in your
example... it's kind of strange to have THEN mark the *end*
of the then-branch in an if-then-else construct.

--
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source *(#1, Nov 13 2008)>>Python/Zope Consulting and Support ... * * * *http://www.egenix.com/
>mxODBC.Zope.Database.Adapter ... * * * * * *http://zope.egenix.com/
mxODBC, mxDateTime, mxTextTools ... * * * *http://python.egenix.com/

__________________________________________________ ______________________
2008-11-12: Released mxODBC Connect 0.9.3 * * *http://python.egenix..com/

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::

* *eGenix.com Software, Skills and Services GmbH *Pastor-Loeh-Str.48
* * D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
* * * * * *Registered at Amtsgericht Duesseldorf: HRB 46611
It's interesting to see people think it's strange to have code that
has multiple nested levels of IF THEN. Apparently you haven't seen
any Forth, assembly, et al code. All you're doing is having the branch
point for each conditional be the end of the chain, otherwise it falls
through to the code after the conditional. This is done all the time
in languages that let you actually manipulate the hardware.

Just as a suggestion :-) a little humility would go a long way toward
being open minded and receptive to different paradigms. I've written
this program I'm doing now in Python in 3 other languages (including
Python, which I'm trying to make more efficient) and I seek to be
flexible in my software linguistic capabilities.

I asked a very narrow question about a very specific language
mechanism, and I know exactly what and why I'm doing what I'm doing.

I'll try some of the suggestions and see if they make the routine
faster in Python.
Nov 13 '08 #8

P: n/a
On 2008-11-14 00:19, jzakiya wrote:
On Nov 13, 5:48 pm, "M.-A. Lemburg" <m...@egenix.comwrote:
>>>From: jzakiya <jzak...@mail.com>
To: python-l...@python.org
Sent: Thursday, November 13, 2008 5:06:53 PM
Subject: Python IF THEN chain equivalence
I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN
You should probably consider using a function and then
convert the conditions to define return points:

def do_something(...args...):

if x1 >= limit:
return
...do a...
if x2 >= limit:
return
...do b...
etc.

That is provided I understand the flow of control in your
example... it's kind of strange to have THEN mark the *end*
of the then-branch in an if-then-else construct.

It's interesting to see people think it's strange to have code that
has multiple nested levels of IF THEN.
Not at all, that's fairly common in a lot of languages. It's not
common to mark the end of the then-part using the THEN keyword,
though. You'd normally expect the body of the then-part after the
keyword.
Apparently you haven't seen
any Forth, assembly, et al code. All you're doing is having the branch
point for each conditional be the end of the chain, otherwise it falls
through to the code after the conditional. This is done all the time
in languages that let you actually manipulate the hardware.

Just as a suggestion :-) a little humility would go a long way toward
being open minded and receptive to different paradigms.
Without giving any hint as to what the quoted snippet
of code is written in, how do you expect people to make
any sense of it ? Especially when using an RPN stack oriented
language in a Python forum.

There's a reason why we hide Python byte code running on the
VM stack machine from Python users ;-)

--
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source (#1, Nov 14 2008)
>>Python/Zope Consulting and Support ... http://www.egenix.com/
mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/
mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/
__________________________________________________ ______________________
2008-11-12: Released mxODBC Connect 0.9.3 http://python.egenix.com/

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::
eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
Registered at Amtsgericht Duesseldorf: HRB 46611
Nov 14 '08 #9

P: n/a
jzakiya:
I asked a very narrow question about a very specific language
mechanism, and I know exactly what and why I'm doing what I'm doing.
You are of course free to use Python as you want. And probably some of
the answers weren't fully polite.
But it's interesting to see why they have given such answers. While
your code can be fit for Forth or assembly, it may be unfit, in its
current form, for the usual practices of Python programming (or C#/
Java programming, etc). In high-level languages large trees of very
nested ifs are seen as error-prone, not much readable, brittle... So
some alternative solutions are often used (even if they may be a
little slower).
If you need speed you may use Psyco too.

Bye,
bearophile
Nov 14 '08 #10

P: n/a
On Nov 13, 4:39*pm, Grant Edwards <invalid@invalidwrote:
On 2008-11-13, jzakiya <jzak...@mail.comwrote:
I'm translating a program in Python that has this IF Then chain
IF *x1 < limit: * --- do a ---
* * IF *x2 < limit: *--- do b ---
* * * * IF x3 < limit: *--- do c ---
* * * * * * * * * * * *.-----
* * * * * * * * * * * * ------
* * * * * * * * * * IF *x10 < limt: --- do j ---
* * * * * * * * * * THEN
* * * * * * * * *THEN
* * * * * * * -----
* * * * * THEN
* * *THEN
THEN

The placement of the THEN statements makes absolutely no sense
in any language I've ever seen.
It looks like Visual Basic.

IF a THEN
do_a
IF b THEN
do_b
IF c THEN
do_c
END IF
END IF
END IF

Words different, but same structure.
>
In other words, as long as * *'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.
Is this the equivalence in Python?
*IF *x1 < limit:
* * * * --- do a *---
*elif x2 < limit:
* * * * --- do b ---
*----
*----
*elif x10 < limit:
* * * *--- do j ---

No. *That's not the same at all.

Here's one solution:

while True:
* if x1 limit: break
* do a
* if x2 limit: break
* do b
* if x3 limit: break
* do c
* ...
* if x10 limit: break
* do j
* break *

--
Grant Edwards * * * * * * * * * grante * * * * * * Yow! Eisenhower!! *Your
* * * * * * * * * * * * * * * * * at * * * * * * * mimeograph machine upsets
* * * * * * * * * * * * * * * *visi.com * * * * * *my stomach!!
Nov 14 '08 #11

P: n/a
jzakiya wrote:
I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.
if x1 < limit:
do a
if x2 < limit:
do b
if x3 < limit:
do c
Nov 14 '08 #12

P: n/a
On 2008-11-14, Ethan Furman <et***@stoneleaf.uswrote:
jzakiya wrote:
>I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.

if x1 < limit:
do a
if x2 < limit:
do b
if x3 < limit:
do c
.
.
.
etc
That doesn't do what the OP specified. If any of the
conditions fail, it should "jump" to the end and not execute
_any_ further "do" statements regardless of the values of
subsequent conditions.
On the plus side, it's easy to read and understand -- on the
minus side, it doesn't jump to the end once the tests start
failing.
If all you want is easy to read and understand, then this is
event simpler:
sys.exit(0)

--
Grant

Nov 14 '08 #13

P: n/a
Grant Edwards wrote:
On 2008-11-14, Ethan Furman <et***@stoneleaf.uswrote:
>jzakiya wrote:
>>I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN

In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.
if x1 < limit:
do a
if x2 < limit:
do b
if x3 < limit:
do c
.
.
.
etc

That doesn't do what the OP specified. If any of the
conditions fail, it should "jump" to the end and not execute
_any_ further "do" statements regardless of the values of
subsequent conditions.
Ack -- I was aware of the lack of jump, but missed that x7 might be less
than limit even if x6 is greater -- thanks.
>On the plus side, it's easy to read and understand -- on the
minus side, it doesn't jump to the end once the tests start
failing.

If all you want is easy to read and understand, then this is
event simpler:
sys.exit(0)
<sheepish grin>
~ethan~
Nov 14 '08 #14

P: n/a
On Fri, 14 Nov 2008 01:24:32 +0100, M.-A. Lemburg wrote:
>Apparently you haven't seen
any Forth, assembly, et al code. All you're doing is having the branch
point for each conditional be the end of the chain, otherwise it falls
through to the code after the conditional. This is done all the time
in languages that let you actually manipulate the hardware.

Just as a suggestion a little humility would go a long way toward
being open minded and receptive to different paradigms.

Without giving any hint as to what the quoted snippet of code is written
in, how do you expect people to make any sense of it ? Especially when
using an RPN stack oriented language in a Python forum.

There's a reason why we hide Python byte code running on the VM stack
machine from Python users ;-)
It's not like Forth is precisely an obscure little language. For a time,
it was possibly more popular than C. Or predated C? Whatever. I know I
learned about Forth long before I had even heard of C.

Other RPN languages include Postscript, not exactly unheard of either.
Open Firmware is Forth-like, and as you point out yourself, Python byte
code also is a stack-based language.

In conclusion, I'm not sure which is more disappointing: that the OP
couldn't be bothered to mention he was using a Forth-like syntax, or that
so many people failed to recognize it.

Anyway, for what it's worth, here's my translation into Python.

if x1 < limit:
a()
if x2 < limit:
b()
if x3 < limit:
c()
# blah blah blah...
if x10 < limt:
j()
Not very nice code. I think a better way is something like this:

keys = [x1, x2, x3, x4, x5, x6, x7, x8, x9, x10]
functions = [a, b, c, d, e, f, g, h, i, j]

for key, function in zip(keys, functions):
if key < limit:
function()
else:
break

--
Steven
Nov 14 '08 #15

P: n/a
jzakiya wrote:
On Nov 13, 5:48 pm, "M.-A. Lemburg" <m...@egenix.comwrote:
>On 2008-11-13 23:31, jzakiya wrote:
>>On Nov 13, 5:21 pm, Alan Baljeu <alanbal...@yahoo.comwrote:
I think you should rethink your post. The first case you posted makes no sense in any language I know. Also, a whole lot of nested IF's is a bad idea in any language. In Python, you will end up with code indented 40+ characters if you keep going.
----- Original Message ----
From: jzakiya <jzak...@mail.com>
To: python-l...@python.org
Sent: Thursday, November 13, 2008 5:06:53 PM
Subject: Python IF THEN chain equivalence
I'm translating a program in Python that has this IF Then chain
IF x1 < limit: --- do a ---
IF x2 < limit: --- do b ---
IF x3 < limit: --- do c ---
.-----
------
IF x10 < limt: --- do j ---
THEN
THEN
-----
THEN
THEN
THEN
In other words, as long as 'xi' is less than 'limit' keep going
down the chain, and when 'xi' isn't less than 'limit' jump to end of
chain a continue.
Is this the equivalence in Python?
IF x1 < limit:
--- do a ---
elif x2 < limit:
--- do b ---
----
----
elif x10 < limit:
--- do j ---
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In the code the 'xi's and 'limit' are variables and the --- do letters
---
phrases are simply writes to any array: an_array[xi]=0
Actually, the code makes perfectly good sense, and is a necessity of
the algorithm I'm implementing, and works perfectly good in Forth, and
can be
written quite nicely within a normal page width.
I was just hoping I could perform the equivalent chain in Python
without
having to grossly indent the source code past the normal width of a
printed page.
But if that's the only way to do it in Python, then so be it.
You should probably consider using a function and then
convert the conditions to define return points:

def do_something(...args...):

if x1 >= limit:
return
...do a...
if x2 >= limit:
return
...do b...
etc.

That is provided I understand the flow of control in your
example... it's kind of strange to have THEN mark the *end*
of the then-branch in an if-then-else construct.

--
Marc-Andre Lemburg
eGenix.com

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It's interesting to see people think it's strange to have code that
has multiple nested levels of IF THEN. Apparently you haven't seen
any Forth, assembly, et al code. All you're doing is having the branch
point for each conditional be the end of the chain, otherwise it falls
through to the code after the conditional. This is done all the time
in languages that let you actually manipulate the hardware.

Just as a suggestion :-) a little humility would go a long way toward
being open minded and receptive to different paradigms. I've written
this program I'm doing now in Python in 3 other languages (including
Python, which I'm trying to make more efficient) and I seek to be
flexible in my software linguistic capabilities.

I asked a very narrow question about a very specific language
mechanism, and I know exactly what and why I'm doing what I'm doing.
Well in my case what you are doing is pissing me off by failing to
explain your original requirements sufficiently well and then taking a
condescending attitude towards genuine efforts to help by people whose
reputations I know and respect.

One wonders why someone at your stratospheric ability level would even
need any help from the likes of us.

You talk about the need for humility: physician, heal thyself. However
good you may be at software, you demonstrate a marked lack of
interpersonal skills.
I'll try some of the suggestions and see if they make the routine
faster in Python.
That's a good idea.

regards
Steve
--
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/

Nov 17 '08 #16

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