Use the power of pandas / numpy to transform tabular datasets in a myriad of ways with our new Table Compute tool
With Table Compute you can:
 drop or duplicate given rows or columns from a tabular dataset
 filter rows or columns on their properties
 replace or transform table elements
 compute tables of summary statistics across rows or columns
It is even possible to manipulate individual tables or combine multiple ones using pandas/numpybased custom expressions!
In short, whatever functionality for manipulating tabular data you may have missed in Galaxy is likely provided by this tool, so give it a try in your next analysis. We are looking forward to your feedback!
Some ideas what you may use the tool for include
 transpose a tabular dataset
 logtransform the data, but add a small offset to zerovalues first
 subtract a table from another
 normalize rows or columns
To get you started, here are some concrete stepbystep examples taken directly from the help section of the tool:
Example 1: Subselecting from a table
We have the following table:
c1  c2  c3  

g1  10  20  30 
g2  3  6  9 
g3  4  8  12 
g4  81  6  3 
and we want to duplicate c1 and remove c2. Also select g1 to g3 and add g2 at the end as well. This would result in the output table:
c1  c1  c3  

g1  10  10  30 
g2  3  3  9 
g3  4  4  12 
g2  3  3  9 
In Galaxy we would select the following:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Drop, keep or duplicate rows and
columns
 List of columns to select → 1,1,3
 List of rows to select → 1:3,2
 Keep duplicate columns → Yes
 Keep duplicate rows → Yes
Example 2: Filter for rows with row sums less than 50
We have the following table:
c1  c2  c3  

g1  10  20  30 
g2  3  6  9 
g3  4  8  12 
g4  81  6  3 
and we want:
c1  c2  c3  

g2  3  6  9 
g3  4  8  12 
In Galaxy we would select the following:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Filter rows or columns by their
properties
 Filter → Rows
 Filter Criterion → Result of function applied to
columns/rows
 Keep column/row if its observed → Sum
 is → < (Less Than)
 this value → 50
Example 3: Count the number of values per row smaller than a specified value
We have the  following table: 
c1  c2  c3  

g1  10  20  30 
g2  3  6  9 
g3  4  8  12 
g4  81  6  3 
and we want to count how many elements in each row are smaller than 10, i.e., we want to obtain the following results table:
vec  

g1  0 
g2  3 
g3  2 
g4  2 
In Galaxy we would select the following:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Manipulate selected table elements
 Operation to perform → Custom
 Custom Expression on ‘elem’ → elem < 10
 Operate on elements → All
 Operation to perform → Custom
Note: There are actually simpler ways to achieve our purpose, but here we are demonstrating the use of a custom expression.
After executing, we would then be presented with a table like so:
c1  c2  c3  

g1  False  False  False 
g2  True  True  True 
g3  True  True  False 
g4  False  True  True 
To get to our desired table, we would then process this table with the tool again:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Compute Expression across Rows or
Columns
 Calculate → Sum
 For each → Row
Executing this will sum all the ‘True’ values in each row. Note that the values must have no extra whitespace in them for this to work (e.g. ‘True ‘ or ‘ True’ will not be parsed correctly).
Example 4: Perform a scaled logtransformation conditionally
We want to perform a scaled log transformation on all values greater than 5, and set all other values to 1.
We have the following table:
c1  c2  c3  

g1  0  20  30 
g2  3  0  9 
g3  4  8  0 
g4  81  0  0 
and we want:
c1  c2  c3  

g1  1.00000000  0.1497866  0.1133732 
g2  1.00000000  1.0000000  0.2441361 
g3  1.00000000  0.2599302  1.0000000 
g4  0.05425246  1.0000000  1.0000000 
In Galaxy we would select the following:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Manipulate selected table elements
 Operation to perform → Custom

Custom Expression → :
(math.log(elem) / elem) if (elem > 5) else 1

Operate on elements → All

 Operation to perform → Custom
Example 5: Perform a Full table operation
We have the following table:
c1  c2  c3  

g1  10  20  30 
g2  3  10  9 
g3  4  8  10 
g4  81  10  10 
and we want to subtract from each column the mean of that column divided by the standard deviation of it to yield:
c1  c2  c3  

g1  9.351737  17.784353  28.550737 
g2  2.351737  7.784353  7.550737 
g3  3.351737  5.784353  8.550737 
g4  80.351737  7.784353  8.550737 
In Galaxy we would select the following:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Perform a Full Table Operation
 Operation → Custom

Custom Expression on ‘table’ along axis (0 or 1) → :
table  table.mean(0)/table.std(0)
Example 6: Perform operations on multiple tables
We have the following three input tables:
Table 1
c1  c2  c3  

g1  10  20  30 
g2  3  10  9 
g3  4  8  10 
Table 2
c1  c2  

g1  1  2 
g2  3  4 
g3  6  5 
Table 3
c1  c2  c3  

g1  1  2  3 
g2  1  2  3 
Note that the dimensions of these tables do not match.
 Dimensions:

 Table1 [3,3]
 Table2 [3,2]
 Table3 [2,3]
In order to perform simple operations between Tables, they must be of the same dimensions.
To add Table2 to Table3 we would have to transpose one of the tables using the inbuilt T method:
table2 + table3.T
or:
table2.T + table3
We can also perform more general operations using all 3 tables, such as taking the minimum value of the maximum values of Table2 and Table3, and dividing the Table1 values by it:
table1 / min(table2.values.max(), table3.values.max())
To perform these types of operations in Galaxy we would select the following:
 Input Single or Multiple Tables → Multiple Tables

 (For each inserted table)

 Column names on first row? → Yes
 Row names on first column? → Yes

Custom Expression → :
<insert your desired function>
Please note that the last example shown above was chosen to illustrate the limitations of the tool. Nested attributes like table2.values.max are disallowed in expressions in the tool so the above would have to be replaced with the harder to read workaround:
table1 / min(np.max(np.max(table2)), np.max(np.max(table3)))
Also note that, currently min(), max() and sum() are the only builtin Python functions that can be used inside expressions. If you want to use additional functions, these have to be qualified functions from the math, np or pd libraries.
Example 7: Melt
We have the following table
A  B  C  

0  a  B  1 
1  b  B  3 
2  c  B  5 
and we want:
A  variable  value  

0  a  B  B 
1  b  B  B 
2  c  B  B 
3  a  C  1 
4  b  C  3 
5  c  C  5 
In Galaxy we would select the following:
 Input Single or Multiple Tables → Single Table
 Column names on first row? → Yes
 Row names on first column? → Yes
 Type of table operation → Perform a Full Table Operation
 Operation → Melt
 Variable IDs → “A”
 Unpivoted IDs → “B,C”
This converts the “B” and “C” columns into variables.
Example 8: Pivot
We have the following table
foo  bar  baz  zoo  

0  one  A  1  x 
1  one  B  2  y 
2  one  C  3  z 
3  two  A  4  q 
4  two  B  5  w 
5  two  C  6  t 