Python getting a string (key + value) from Python Dictionary

Question

I have dictionary structure. For example:

dict = {key1 : value1 ,key2 : value2}

What I want is the string which combines the key and the value

Needed string –>> key1_value1 , key2_value2

Any Pythonic way to get this will help.

Thanks

def checkCommonNodes( id  , rs):
     for r in rs:
         for key , value in r.iteritems():
             kv = key+"_"+value
             if kv == id:
                 print "".join('{}_{}'.format(k,v) for k,v in r.iteritems())

Asked By: Peter

||

Source

Answer 1

A list of key-value strs,

>>> d = {'key1': 'value1', 'key2': 'value2'}
>>> ['{}_{}'.format(k,v) for k,v in d.iteritems()]
['key2_value2', 'key1_value1']

Or if you want a single string of all key-value pairs,

>>> ', '.join(['{}_{}'.format(k,v) for k,v in d.iteritems()])
'key2_value2, key1_value1'

EDIT:

Maybe you are looking for something like this,

def checkCommonNodes(id, rs):
    id_key, id_value = id.split('_')
    for r in rs:
        try:
            if r[id_key] == id_value:
                print "".join('{}_{}'.format(k,v) for k,v in r.iteritems())
        except KeyError:
            continue

You may also be wanting to break after printing – hard to know exactly what this is for.

Answered By: Jared

Answer 2

Assuming Python 2.x, I would use something like this

dict = {'key1': 'value1', 'key2': 'value2'}
str = ''.join(['%s_%s' % (k,v) for k,v in dict.iteritems()])

Answered By: gramonov

Answer 3

def checkCommonNodes(id, rs):
   k,v = id.split('_')
   for d in rs:
       if d.get(k) == v:
           return id
   retun None

Answered By: Burhan Khalid

Answer 4

Updated answer for Python 3.x

Example one – join a single key, value in the form "key_value"

k = 'key1'
v = 'value1'
mystring = f'{k}={v}'
print(mystring)

# result -> key1=value1

Example two: create a list of all key-value pairs as strings in the form "key_value"

mydict = {'key1': 'value1', 'key2': 'value2'}
mylist = [f'{k}_{v}' for k,v in mydict.items()]
print(mylist)

# result -> ['key1_value1', 'key2_value2']

Example three: transform a list to a string

result = ', '.join(mylist)
print(result)

# result -> key1_value1, key2_value2

Putting it all together – join all key-value pairs in a dictionary and output as a string.

mydict = {'key1': 'value1', 'key2': 'value2'}
result = ', '.join([f'{k}_{v}' for k,v in mydict.items()])
print(result)

# result -> key1_value1, key2_value2

This is the same basic answer provided by Jared, but now with Python 3.x we use the .items() function instead of .iteritems(), and we can use an f-string instead of the string format() function (although the latter does still work too).

This may not be exactly the perfect answer to the original question asked 12+ years ago (!) but it is a more generic answer about transforming dictionary key-value pairs to (key + value), as indicated by the question title.

Answered By: topsail

Python getting a string (key + value) from Python Dictionary

Question:

Answers:

Updated answer for Python 3.x

Putting it all together – join all key-value pairs in a dictionary and output as a string.