Retrieve value from list python2.7

Question

My list looks like as follows:

list = [{u'Value': u'Value1', u'Key': u'Key1'}, {u'Value': u'value2', u'Key': u'key2'}]

I would like to retrieve value1, but only if key1 matches a specific string, i'm not sure if i have to iterate over this twice???

Answer 1

You can add a guard to a list comprehension to act as a filter

[d[u"Value"] for d in list if d[u"Key"] == u"Key1"]

You should also avoid shadowing built in names like list

Answer 2

No, you don't need to iterate over the list twice:

value = None
for d in list:
    if d[u"Key"] == u"Key1":
        value = d[u"Value"]

This can be written in one line using next() and a generator:

value = next((d[u"Value"] for d in list if d[u"Key"] == u"Key1"), None)