tuples

I have pseudo-code like this: if( b < a) return (1,0)+foo(a-b,b) I want to write it in python. But can python add tuples? What is the best way to code something like that? Do you want to do element-wise addition, or to append the tuples? By default python does (1,2)+(3,4) = (1,2,3,4) You could define your own as: def myadd(x,y): z = [] for i in range(len(x)): z.append(x[i]+y[i]) return tuple(z) Also, as @delnan's comment makes it clear, this is better written as def myadd(xs,ys): return tuple(x + y for x, y in izip(xs, ys)) or even more functionally: myadd = lambda xs,ys: tuple(x + y for x, y

I have a list of tuples like this: [("username", 123), ("df", 54), ("as",2 34)] I need to search the value based on username. I have using lookup but i need to change the value of the integer and write back to file. My logic of this is to delete the tuple and insert another new tuple value rather than change it. Any idea how to do this ? Use Data.Map like this : import qualified Data.Map as Map m1 :: Map String Int m1 = Map.fromList [("username", 123), ("df", 54), ("as",234)] Let's replace 54 by 78 (on "df"): m2 = Map.insert "df" 78 m1 You can use insertWith' to combine the old and new values

This question already has answers here : Closed 5 years ago . What is the pythonic way to unpack tuples? [duplicate] (2 answers) I'm trying to use the str.format() method, and having some difficulties when my values are stored within a tuple. For example, if I do: s = "x{}y{}z{}" s.format(1,2,3) Then I get 'x1y2z3' - no problem. However, when I try: s = "x{}y{}z{}" tup = (1,2,3) s.format(tup) I get IndexError: tuple index out of range. So how can I 'convert' the tuple into separate variables? or any other workaround ideas? Martijn Pieters Pass in the tuple using *arg variable arguments call

I am writing a little program in python and I am using a dictionary whose (like the title says) keys and values are tuples. I am trying to use json as follows import json data = {(1,2,3):(a,b,c),(2,6,3):(6,3,2)} print json.dumps(data) Problem is I keep getting TypeError: keys must be a string . How can I go about doing it? I tried looking at the python documentation but didn't see any clear solution. Thanks! You'll need to convert your tuples to strings first: json.dumps({str(k): v for k, v in data.iteritems()}) Of course, you'll end up with strings instead of tuples for keys: '{"(1, 2, 3)": [

I am trying to return a tuple the smallest second index value (y value) from a list of tuples. If there are two tuples with the lowest y value, then select the tuple with the largest x value (i.e first index). For example, suppose I have the tuple: x = [(2, 3), (4, 3), (6, 9)] The the value returned should be (4, 3) . (2, 3) is a candidate, as x[0][1] is 3 (same as x[1][1] ), however, x[0][0] is smaller than x[1][0] . So far I have tried: start_point = min(x, key = lambda t: t[1]) However, this only checks the second index, and does not compare two tuples first index if their second index's