python - Edit the values in a list of dictionaries?

Question

my_dicts = [ 
    { 'key1' : 'value1',
      'key2' : 'value2' },

    { 'key1' : 'value1',  
      'key2' : 'value2' },

    { 'key1' : 'value1',  
      'key2' : 'value2' }]

What would be the most efficient way to replace all instances of 'value2' with 'value3' ?

Answer 1

I did not do any timings, but you probably can't get much better than

for d in my_dicts:
    d.update((k, "value3") for k, v in d.iteritems() if v == "value2")

Update for Python3

for d in my_dicts:
    d.update((k, "value3") for k, v in d.items() if v == "value2")