Changes between Version 26 and Version 27 of DeveloperGuidelines/Py_2_3

Timestamp:

06/28/19 08:31:29 (6 years ago)

Author:

Dominic König

Comment:

--

DeveloperGuidelines/Py_2_3

@@ -131 +131 @@
 === Map and Zip return generators ===
 
-In Python-3, the {{{map()}}} and {{{zip()}}} functions return generator objects rather than lists. Where lists are required, the return value must be converted explicitly using the list constructor. Where possible, we prefer list comprehensions.
+In Python-3, the {{{map()}}} and {{{zip()}}} functions return generator objects rather than lists. This is fine when we want to iterate over the result, especially when there is a chance to break out of the loop early.
+
+But where lists are required, the return value must be converted explicitly using the list constructor.
+
 {{{#!python
 # This is fine:
@@ -139 +142 @@
 # This is better:
 result = list(map(func, values))
-# This could be even better (though not for multiple iterables):
+# This could be even better:
 result = [func(v) for v in values]
 }}}
+
+'''NB''' For building a list from a single iterable argument, we prefer list comprehensions over {{{map()}}} for readability and speed.