PEP 276 Simple Iterator for ints (fwd)

[James_Althoff at i2.com]

David Eppstein wrote:
>James_Althoff at i2.com wrote:
>> If not 3), then there is the issue of having to do an extra computation
for
>> the common case of indexing a sequence as in, e.g.,
>>
>>     for i in 0 .. len(sequence)-1:
>
>This is very common in C, but is it so common in Python?
>Isn't it usually more idiomatic to do
>    for item in sequence
>?

Yes, that is the common idiom.

PEP 276 is aimed at cases where "for item in sequence" doesn't work as in,
for example:

    for rowcount in xrange(table.getRowCount()):  # valid Python
        print table.getValueAt(rowcount,0)

    for rowcount in table.getRowCount():  # as proposed in PEP 276
        print table.getValueAt(rowcount,0)

    for rowcount in [0 .. table.getRowCount()-1]:  # Haskell-esque syntax
        print table.getValueAt(rowcount,0)

In this example:

    for row in table.getRows():

doesn't work because there is no "table.getRows()" method that can be
called.  Hence, the need for indexing.
As noted in the PEP, the commonly used (in Jython) Java/Swing/Jython class
DefaultTableModel is an example where there is a "getValueAt" method (that
requires a row index and a column index) but no "getRows" method.

Jim