Jussi Piitulainen wrote:
> Ravi Prabakaran writes:
>
>> I'm completely new to python. I just need simple logic to get output
>> without any loops.
>> I have list of string and list of list of numbers.
>> Each string should be concatenated with every third and fourth
>> values to generate proper titles in list of strings.
>>
>> t = ['Start','End']
>> a = [[1,2,3,4],
>> [5,6,7,8]]
>>
>>
>> Expected Result : ( list of strings )
>>
>> ['Start - 3 , End - 4',
>> 'Start - 7 , End - 8']
>>
>> Note : First 2 values from each list should be ignored.
>>
>>
>> Could anyone please guide me with best solution without loops ?
>
> That's a strange requirement - to have repetition without loops, in
> Python, and still have a best solution.
>
> I suppose it's fine to have a (built-in) function do the looping for
> you so that there is no explicit loop in your own code. The .format
> method of Python strings can do each individual string:
>
> list(map('{2} - {0} , {3} - {1}'
> .format('{0[2]}', '{0[3]}', *t)
> .format, a))
Don't do that if t may contain user data. For the sake of the argument let's
assume that a[...][0:2] is confidential. Then
>>> t = "{0[0]}", "{0[1]}"
>>> list(map('{2} - {0} , {3} - {1}'
... .format('{0[2]}', '{0[3]}', *t)
... .format, a))
['1 - 3 , 2 - 4', '5 - 7 , 6 - 8']
(I think doubling the braces is sufficient to fix this)
> The first (inner) call of .format builds the actual format string
> whose .format method then builds each output string: {0[2]} in a
> format string refers to the argument position 0 and its element
> position 2; *t spreads the two elements of t as further positional
> arguments.
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