Question

I would like to rewrite the python code example from the book to C# equivalent in order to test its functionality.

The code is the following:

q = "select target_id from connection where source_id=me() and target_type='user'"
my_friends = [str(t['target_id']) for t in fql.query(q)]

q = "select uid1, uid2 from friends where uid1 in (%s) and iud2 in (%s)" %
    (",".join(my_friends), ",".join(my_friends),)
mutual_friendships = fql(q)

What I don’t know is sign %s and what (%s) in code means. I would really appreciate if anyone could write the equivalent code in C#.

Answer 1

String formatting operation in Python

%s are replaced with the corresponding values from the tuple passed after % operator.

How it works in Python

For example this:

my_friends = [0, 2, 666, 123132]
print "select uid1 from friends where uid1 in (%s)" % (",".join(my_friends))

would print this:

select uid1 from friends where uid1 in (0,2,666,123132)

How to replace it with C#

You need to use String.Format(), as mentioned eg. here: http://blog.stevex.net/string-formatting-in-csharp/

string formatString = "select uid1, uid2 from friends where uid1 in ({0}) and iud2 in ({1})"
string q = String.Format(formatString, yourReplacement1, yourReplacement2)

It works the way that is very similar to Python’s string format() method (available since Python 2.6).