Do I need a nested lambda to do this?

[raoul]

I can't figure this one out. Trying to be unnecessarily functional I
suspect.

I have the following lists.

vals = [1.000,2.344,4.2342]
tab = [((0,1),(0,3),(0,4)),
((2,2),(3,0),(3,9)),
((3,4),(6,3),(7,1))]

I'm trying to create a one liner using map/reduce/lambda/zip(* etc to
do replace the first element of each pair in each row by the the values
in vals as follows:

tab = [((1.000,1),(1.000,3),(1.000,4)),
((2.344,2),(2.344,0),(2.344,9)),
((4.2342,4),(4.2342,3),(4.2342,1))]

I'm pretty sure there's a oneline way to do this. Naturally, one could
loop mindlessly but this is my self-imposed programming challenge for
the day and I'm not feeling much love from my python.

 

[R. C. James Harlow]

I can't figure this one out. Trying to be unnecessarily functional I
suspect.

With list comprehensions:

Python 2.3.4 (#1, Mar 26 2005, 20:54:10)
[GCC 3.3.4 20040623 (Gentoo Linux 3.3.4-r1, ssp-3.3.2-2, pie-8.7.6)] on linux2
Type "help", "copyright", "credits" or "license" for more information.

vals = [1.000,2.344,4.2342]
tabs = [((0,1),(0,3),(0,4)),

.... ((2,2),(3,0),(3,9)),
.... ((3,4),(6,3),(7,1))]

[(tuple([(vals[index],subtab[1]) for subtab in tab])) for index,tab in

enumerate(tabs)]
[((1.0, 1), (1.0, 3), (1.0, 4)), ((2.3439999999999999, 2),
(2.3439999999999999, 0), (2.3439999999999999, 9)), ((4.2342000000000004, 4),
(4.2342000000000004, 3), (4.2342000000000004, 1))]

 

[Bill Mill]

I can't figure this one out. Trying to be unnecessarily functional I
suspect.

With list comprehensions:

Python 2.3.4 (#1, Mar 26 2005, 20:54:10)
[GCC 3.3.4 20040623 (Gentoo Linux 3.3.4-r1, ssp-3.3.2-2, pie-8.7.6)] on linux2
Type "help", "copyright", "credits" or "license" for more information.

vals = [1.000,2.344,4.2342]
tabs = [((0,1),(0,3),(0,4)),

... ((2,2),(3,0),(3,9)),
... ((3,4),(6,3),(7,1))]

[(tuple([(vals[index],subtab[1]) for subtab in tab])) for index,tab in

enumerate(tabs)]
[((1.0, 1), (1.0, 3), (1.0, 4)), ((2.3439999999999999, 2),
(2.3439999999999999, 0), (2.3439999999999999, 9)), ((4.2342000000000004, 4),
(4.2342000000000004, 3), (4.2342000000000004, 1))]

Slightly nicer, I think:

vals [1.0, 2.3439999999999999, 4.2342000000000004]
tabs [((0, 1), (0, 3), (0, 4)), ((2, 2), (3, 0), (3, 9)), ((3, 4), (6, 3), (7, 1))]
[tuple([(v, t[1]) for t in tab]) for v, tab in zip(vals, tabs)]

[((1.0, 1), (1.0, 3), (1.0, 4)),
((2.3439999999999999, 2), (2.3439999999999999, 0),
(2.3439999999999999, 9)),
((4.2342000000000004, 4), (4.2342000000000004, 3),
(4.2342000000000004, 1))]

Peace
Bill Mill
bill.mill at gmail.com

 

[Kent Johnson]

I can't figure this one out. Trying to be unnecessarily functional I
suspect.

I have the following lists.

vals = [1.000,2.344,4.2342]
tab = [((0,1),(0,3),(0,4)),
((2,2),(3,0),(3,9)),
((3,4),(6,3),(7,1))]

I'm trying to create a one liner using map/reduce/lambda/zip(* etc to
do replace the first element of each pair in each row by the the values
in vals as follows:

tab = [((1.000,1),(1.000,3),(1.000,4)),
((2.344,2),(2.344,0),(2.344,9)),
((4.2342,4),(4.2342,3),(4.2342,1))]

I don't know about map/etc but it's pretty easy using list comp and gen exp:
print [ tuple( (val, t[1]) for t in tt ) for val, tt in zip(vals, tab) ]

Kent

 

[raoul]

very nice bill. thanks all.