# making two columns from 1D-horizontal data [closed]

Let's say there is imported 1D horizontal data such as:

{{1, 0.01, 4, 0.05, 5, 0.003, 6, 0.07, 31, 0.1, 8, 0.82, 9, 0.74, 11, 0.1, 40, 0.03, 30, 0.05, 53, 0.07, 121, 0.001, 45, 0.06 ...}} (*thousand data*)


I would like to re-arrange it to two columns to calculate some statistics.

As you can see the above 1D data, 1st, 3rd, 5th, 7th, 9th, ... data has random value and 2nd, 4th, 6th, 8th ... data has its error percentage.

How can I change horizontal dataset to vertical that has two column?

1 0.01
4 0.05
5 0.003
6 0.07
31 0.1
8 0.82


AND how can I select the first column only and the second column only?

Thank you so much in advance

• Partition[list[[1]], 2]. To get the first column: Partition[list[[1]], 2][[All, 1]]. To get the second, Partition[list[[1]], 2][[All, 2]]. – march Feb 10 '17 at 19:25
• reference.wolfram.com/language/guide/ListManipulation.html – Kuba Feb 10 '17 at 20:23

Similar to the comment by March:

In[1]:= data = {{1, 0.01, 4, 0.05, 5, 0.003, 6, 0.07, 31, 0.1, 8,
0.82, 9, 0.74, 11, 0.1, 40, 0.03, 30, 0.05, 53, 0.07, 121, 0.001,
45, 0.06 ...}} ;

In[2]:= partitioned = Partition[data[[1]], 2]

Out[2]= {{1, 0.01}, {4, 0.05}, {5, 0.003}, {6, 0.07}, {31, 0.1}, {8,
0.82}, {9, 0.74}, {11, 0.1}, {40, 0.03}, {30, 0.05}, {53,
0.07}, {121, 0.001}, {45, 0.06 ...}}

In[3]:= {column1, column2} = Transpose[partitioned]

Out[3]= {{1, 4, 5, 6, 31, 8, 9, 11, 40, 30, 53, 121, 45}, {0.01, 0.05,
0.003, 0.07, 0.1, 0.82, 0.74, 0.1, 0.03, 0.05, 0.07, 0.001,
0.06 ...}}