i'm  a little confused a puzzled when it comes to the following : list  {{"1,78 ", 323}, {"1,78 ", 3371}, {"1,77 ", 20}, {"1,79 ", 
  10}, {"1,77 ", 400}, {"1,78 ", 600}, {"1,77 ", 1140}, {"1,77 ", 
  90}, {"1,77 ", 10}, {"1,75 ", 50}, {"1,77 ", 1900}, {"1,77 ", 
  1490}, {"1,77 ", 10}, {"1,75 ", 3407}, {"1,74 ", 1500}, {"1,74 ", 
  4500}, {"1,74 ", 323}, {"1,75 ", 3000}, {"1,75 ", 3623}, {"1,75 ", 
  1377}, {"1,75 ", 1000}, {"1,75 ", 800},....}
 For example :Map[Head, Take[%, {15}], {2}] and its out :{{String, Integer}} . Why I can not convert string for real when using ToExpression ?