Apply function on all values of dictionary [duplicate]

Question

I have dictionary that look like

d= {(1, 8): 94.825000000000003, (2, 8): 4.333}

I am trying to apply a function to round all the values.

I don't wanna re-create the dictionary.

newD= {}
for x,y in d.iteritems():
   newD+= {x:round(y)}

Is there any pythonic-way to apply round function on all values ?

Answer 1

This is a little more convoluted, but you did ask for a 'pythonic-way' ;)

newD = {k:round(v) for k, v in d.items()}

However, this dictionary comprehension will only work on 2.7+. If using an older version of Python, try this more convoluted way:

newD = dict(zip(d.keys(), [round(v) for v in d.values()]))

Let me unpack this a little bit:

• We are beginning by reassigning the new dictionary (d) object back to a new dictionary as requested (although you could easily assign it to the same name)
• The outer dict() ensures the final result is a dictionary object
• zip() returns a list of tuples, where the i-th tuple contains the i-th element from each of the argument sequences
• The first argument sequence given to zip() is the dictionary keys (d.keys())
• The second argument sequence given to zip() is the rounded values after a list comprehension
• The list comprehension rounds each value in the dictionary values and returns a list of the rounded values