Confusion about Python list slice results -

I'm new to Python, I'm getting a simple list slice operation.

Here is the code.

  & gt; & Gt; & Gt; A = [1,2,3,4]; & Gt; & Gt; & Gt; One [1: 3] [2, 3]> gt; & Gt; & Gt; A code [3] 4   
 to  no [1: 3]  instead of  [2,3,4]  [2,3] ?  
 
 
 
  one [1: 3]  one  half stop interval < / Em>, which means that the  1  values ​​starting with the specified index,  but not included   2  index < / P> 
 In this case,  a [1: 3]  means that in slices,  a [1]  and  a [2] , but  no   a [3]   
 You will see similar in use. For example,  
  will generate a list from category 1 to 4 (1, 5)   
 but  not  5 Will be included.  
 It is very consistent that how many programming languages ​​are used in