<p>I have a CSV data file with rows that may have lots of columns 500+ and some with a lot less.  I need to transpose it so that each row becomes a column in the output file.  The problem is that the rows in the original file may not all have the same number of columns so when I try the transpose method of array I get:</p>

<blockquote>
  <p>`transpose': element size differs (12 should be 5) (IndexError)</p>
</blockquote>

<p>Is there an alternative to transpose that works with uneven array length?</p>

I would insert nulls to fill the holes in your matrix, something such as:
```
```
a = [[1, 2, 3], [3, 4]]

# This would throw the error you're talking about
# a.transpose

# Largest row
size = a.max { |r1, r2| r1.size <=> r2.size }.size

# Enlarge matrix inserting nils as needed
a.each { |r| r[size - 1] ||= nil }

# So now a == [[1, 2, 3], [3, 4, nil]]
aa = a.transpose

# aa == [[1, 3], [2, 4], [3, nil]]
```
```