# BisectList

Contributed by: George Beck

Make a pair of lists consisting of alternate terms from the original list

 ResourceFunction["BisectList"][{a1,a2,a3,a4,a5,a6,…}] makes the list {{a1,a3,a5…,{a2,a4,a4,…}}.

## Details and Options

ResourceFunction["BisectList"] is a partial inverse function of .
The two sublists have equal lengths.
If the input list has an odd number of terms, the last term is ignored.
The argument can be an expression other than a list.

## Examples

### Basic Examples

The lists being riffled have the same length:

 In[1]:=
 Out[1]=

BisectList gives back the sublists:

 In[2]:=
 Out[2]=

Here the riffled lists have different lengths:

 In[3]:=
 Out[3]=

BisectList ignores the last term:

 In[4]:=
 Out[4]=

Here the head of the expression is not a list:

 In[5]:=
 Out[5]=

### Scope

Add consecutive pairs of a list:

 In[6]:=
 Out[6]=

BisectList twice:

 In[7]:=
 Out[7]=

Pull out the interleaved subsequences, making them both positive:

 In[8]:=
 Out[8]=
 In[9]:=
 Out[9]=