Question

I would like to inquire if there is an elegant pythonic way of executing some function on the first loop iteration.
The only possibility I can think of is:

first = True
for member in something.get():
    if first:
        root.copy(member)
        first = False
    else:
        somewhereElse.copy(member)
    foo(member)

Answer 1

You have several choices for the Head-Tail design pattern.

seq= something.get()
root.copy( seq[0] )
foo( seq[0] )
for member in seq[1:]:
    somewhereElse.copy(member)
    foo( member )

Or this

seq_iter= iter( something.get() )
head = seq_iter.next()
root.copy( head )
foo( head )
for member in seq_iter:
    somewhereElse.copy( member )
    foo( member )

People whine that this is somehow not “DRY” because the “redundant foo(member)” code. That’s a ridiculous claim. If that was true then all functions could only be used once. What’s the point of defining a function if you can only have one reference?