def pop_data_point(self, n):
<EOL>popped = []<EOL>for k in self.ckeys:<EOL><INDENT>data = list(self.c(k))<EOL>popped.append(data.pop(n))<EOL>self.insert_column(_n.array(data), k)<EOL><DEDENT>return popped<EOL>
This will remove and return the n'th data point (starting at 0) from
all columns.

Parameters
----------
n       
    Index of data point to pop.