iterable-unpacking

What I came up with is: keys, values = zip(*[(key, value) for (key, value) in my_dict.iteritems()]) But I am not satisfied. What do the pythonistas say? Constantinius What about using my_dict.keys() and my_dict.values() ? keys, values = my_dict.keys(), my_dict.values() keys, values = zip(*d.items()) 来源： https://stackoverflow.com/questions/6612769/is-there-a-more-elegant-way-for-unpacking-keys-and-values-of-a-dictionary-into-t

I'm frequently using shift to unpack function parameters: sub my_sub { my $self = shift; my $params = shift; .... } However, many on my colleagues are preaching that shift is actually evil. Could you explain why I should prefer sub my_sub { my ($self, $params) = @_; .... } to shift ? The use of shift to unpack arguments is not evil. It's a common convention and may be the fastest way to process arguments (depending on how many there are and how they're passed). Here's one example of a somewhat common scenario where that's the case: a simple accessor. use Benchmark qw(cmpthese); sub Foo::x

Zed Shaw's "Learn Python the Hard Way" frequently asks you to "write out in English" what each and every line of a script does. I am struggling to do that with some stuff associated with the function (command?) argv because I don't know what to name certain parts of the code. Heck, I don't even know what to call argv--a function? A command? Variable? I know it's a module. But back on track: Here is the code from exercise 13 : from sys import argv script, first, second, third = argv print "The script is called:", script print "Your first variable is:", first print "Your second variable is:",

I'm reading a file and unpacking each line like this: for line in filter(fh): a, b, c, d = line.split() However, it's possible that line may have more or fewer columns than the variables I wish to unpack. In the case when there are fewer, I'd like to assign None to the dangling variables, and in the case where there are more, I'd like to ignore them. What's the idiomatic way to do this? I'm using python 2.7. Fix the length of the list, padding with None . def fixLength(lst, length): return (lst + [None] * length)[:length] First of all, think about why you want to do this. However, given that

I am trying to unpack set of phone numbers from a sequence, python shell in turn throws an invalid syntax error. I am using python 2.7.1. Here is the snippet >>> record = ('Dave', 'dave@example.com', '773-555-1212', '847-555-1212') >>> name, email, *phone-numbers = record SyntaxError: invalid syntax >>> Please explain. Is there any other way of doing the same? You are using Python 3 specific syntax in Python 2. The * syntax for extended iterable unpacking in assignments is not available in Python 2. See Python 3.0, new syntax and PEP 3132 . Use a function with * splat argument unpacking to

Let's say I have a method definition like this: def myMethod(a, b, c, d, e) Then, I have a variable and a tuple like this: myVariable = 1 myTuple = (2, 3, 4, 5) Is there a way I can pass explode the tuple so that I can pass its members as parameters? Something like this (although I know this won't work as the entire tuple is considered the second parameter): myMethod(myVariable, myTuple) I'd like to avoid referencing each tuple member individually if possible... You are looking for the argument unpacking operator * : myMethod(myVariable, *myTuple) From the Python documentation : The reverse