This section lists common Python coding tricks and general usage hints. Consult the Python Library Reference and Python Language Reference (http://www.python.org/doc/) for further information on topics mentioned here.
S[:] makes a top-level (shallow) copy of any sequence;
copy.deepcopy(X) makes full
copies; list(L) and D.copy() copy lists and
dictionaries.
L[:0]=[X,Y,Z] inserts
items at front of list L,
in-place.
L[len(L):]=[X,Y,Z],
L.extend([X,Y,Z]), and L +=
[X,Y,Z] all insert multiple
items at the end of a list, in-place.
L.append(X) and X=L.pop() can be used to implement
in-place stack operations, where the end of the list is the top of
the stack.
Use for key in D.keys():
to iterate through dictionaries, or simply for key in D: in version 2.2 and later.
In Python 3.0 these two forms are equivalent, since keys is an iterable view.
Use for key in sorted(D):
to iterate over dictionary keys in sorted fashion in version 2.4
and later; the form K=D.keys(); K.sort();
for key in K: also works in Python 2.X but not Python 3.0, since
keys results are view objects,
not lists.
X=A or B or None assigns
X to the first true object
among A and B, or None if both are false (i.e., 0 or
empty).
X,Y = Y,X swaps the
values of X and Y.
red, green, blue =
range(3) assigns integer series.
Use try/finally
statements to ensure that arbitrary termination code is run;
especially useful around locking calls (acquire before the
try, release in the finally).
Use with/as statements ...
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