[exec cmd for cmd in cmds]

[Schüle Daniel]

Hello all,
[color=blue][color=green][color=darkred]
>>> p = "z%i = complex(1-1e-%i, 1-1e-%i)"
>>> lst = [p % (i,i,i) for i in range(10, 30)]
>>> for item in lst:[/color][/color][/color]
.... exec item
....[color=blue][color=green][color=darkred]
>>>
>>> p = "z%i = complex(1-1e-%i, 1-1e-%i)"
>>> lst = [p % (i,i,i) for i in range(10, 30)]
>>> [exec item for item in lst][/color][/color][/color]
File "<stdin>", line 1
[exec item for item in lst]
^
SyntaxError: invalid syntax[color=blue][color=green][color=darkred]
>>>[/color][/color][/color]

is this prohibited for some reasons or is this just happens to be
disallowed?


this is one more cool way[color=blue][color=green][color=darkred]
>>> p = "z%i = complex(1-1e-%i, 1-1e-%i);"
>>> c = reduce(lambda x,y: x+y, [p % (i,i,i) for i in range(20,30)])
>>> exec c[/color][/color][/color]

and one more :)[color=blue][color=green][color=darkred]
>>> p = "z%i = complex(1-1e-%i, 1-1e-%i);"
>>> c = "".join([ p % (i,i,i) for i in range(20,30) ])
>>> exec c[/color][/color][/color]

Regards, Daniel

[Diez B. Roggisch]

Re: [exec cmd for cmd in cmds]

Schüle Daniel wrote:
[color=blue]
> Hello all,
>[color=green][color=darkred]
> >>> p = "z%i = complex(1-1e-%i, 1-1e-%i)"
> >>> lst = [p % (i,i,i) for i in range(10, 30)]
> >>> for item in lst:[/color][/color]
> ... exec item
> ...[color=green][color=darkred]
> >>>
> >>> p = "z%i = complex(1-1e-%i, 1-1e-%i)"
> >>> lst = [p % (i,i,i) for i in range(10, 30)]
> >>> [exec item for item in lst][/color][/color]
> File "<stdin>", line 1
> [exec item for item in lst]
> ^
> SyntaxError: invalid syntax[color=green][color=darkred]
> >>>[/color][/color]
>
> is this prohibited for some reasons or is this just happens to be
> disallowed?[/color]

exec is a statement. And statements aren' allowed in the _expression_ of a
list-comprehension.
[color=blue]
> this is one more cool way[color=green][color=darkred]
> >>> p = "z%i = complex(1-1e-%i, 1-1e-%i);"
> >>> c = reduce(lambda x,y: x+y, [p % (i,i,i) for i in range(20,30)])
> >>> exec c[/color][/color]
>
> and one more :)[color=green][color=darkred]
> >>> p = "z%i = complex(1-1e-%i, 1-1e-%i);"
> >>> c = "".join([ p % (i,i,i) for i in range(20,30) ])
> >>> exec c[/color][/color][/color]

If you think so :) Ususally people go for dictionaries in such cases.

Diez

[Schüle Daniel]

Re: [exec cmd for cmd in cmds]

[...]
[color=blue]
> If you think so :) Ususally people go for dictionaries in such cases.[/color]

you are right, I didn't think about dictionaries
[color=blue][color=green][color=darkred]
>>> p = "complex(1-1e-%i, 1-1e-%i)"
>>> d={}
>>> [d.update({i:eva l(p % (i,i))}) for i in range(20,30)][/color][/color][/color]
[None, None, None, None, None, None, None, None, None, None]

so now the work is complete :)

Regards

[Scott David Daniels]

Re: [exec cmd for cmd in cmds]

Schüle Daniel wrote:[color=blue]
> you are right, I didn't think about dictionaries[color=green][color=darkred]
> >>> p = "complex(1-1e-%i, 1-1e-%i)"
> >>> d={}
> >>> [d.update({i:eva l(p % (i,i))}) for i in range(20,30)][/color][/color]
> [None, None, None, None, None, None, None, None, None, None]
>
> so now the work is complete :)
>
> Regards
>[/color]
Really, isn't this clearer?:

d = {}
for i in range(20, 30):
v = 1. - 10. ** -i
d[i] = complex(v, v)

If you must repair the mess above, try:

p = "complex(1-1e-%i, 1-1e-%i)"
d = dict([(i, eval(p % (i, i))) for i in range(20, 30)])

Strive to be clear first, terse second given the first is still
achieved.

--Scott David Daniels
scott.daniels@a cm.org