python - how to use two variables in for loop? -

define function calls addfirstandlast(x) takes in list of numbers , returns sum of first , last numbers.

examples

>>> addfirstandlast([]) 0 >>> addfirstandlast([2, 7, 3]) 5 >>> addfirstandlast([10]) 10 

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my question can not use 2 variables in loop, should , how fix error. , improved code of problem.

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def addfirstandlast(x):      total = 0     total1 = 0     total2 = 0     pos_last = []     num, last in x:         num = str(num)         num = num[0]         total1 += int(num)         last = last % 10         pos_last = pos_last.append(last)          total = sum(pos_last)         total2 = total+total1     return total2  print addfirstandlast([2, 7, 3]) 

3 distinct cases: 1) list empty, 2) list has 1 element, 3) list has 2 or more elements.

try without loop:

def addfirstandlast(x):     if len(x) == 0:         return 0     elif len(x) < 2:         return x[0]     else:          return x[0]+x[-1]  >>> print addfirstandlast([2, 7, 3]) 5 >>> print addfirstandlast([2, 3]) 5 >>> print addfirstandlast([3]) 3