将字典转换为字符串python

Question

I am trying to convert dictionaries into string

for example:

a={3:4,5:6}
s='3 4, 5 6'

The way I am trying is

s=''
i=0
for (k,v) in d.items():
    s=s+str(k)+' '+str(v)
    while i < len(s):
        if s[i]==str(v) and s[i+1]==str(k):
            s+=s+s[i]+','+s[i+1]

Answer 1

Here's a Pythonic way of doing that using a list comprehension :

s = ', '.join([str(x) + ' ' + str(a[x]) for x in a])

Output:

'3 4, 5 6'

Update: As Julien Spronck mentioned, the square brackets ( [ and ] ) are not necessary. Thus, the following has the same effect:

s = ', '.join(str(x) + ' ' + str(a[x]) for x in a)

---

Working PythonFiddle

Answer 2

You can write the list comprehension expression to get the list of key-value string, then join them on , as

>>> d = {3:4,5:6}
>>> ', '.join('{} {}'.format(k, v) for k, v in d.items())
'3 4, 5 6'

OR, even using repr() ( Note: it is a hack, I consider .join() approach more pythonic ):

>>> repr(d)[1:-1].replace(':', '')
'3 4, 5 6'

Answer 3

I would use the following with a list comprehension:

', '.join([str(k) + ' ' + str(v) for k, v in a.items()])

To illustrate:

In [1]: a = {3:4, 5:6}

In [2]: s = ', '.join([str(k) + ' ' + str(v) for k, v in a.items()])

In [3]: s
Out[3]: '3 4, 5 6'

Answer 4

Of course the most pythonic solution is the one using the list comprehension (see @SumnerEvans and the rest) but just for the sake of having an alternative i will post this here:

a = {3: 4, 5: 6}

v = str(a)
for rep in ['{', '}', ':']:
    v = v.replace(rep, '')
print(v)  # prints -> 3 4, 5 6

Everything can be converted into a string and the manipulated as one. This is what is being done here. From dict to string and then chained replace methods.

Answer 5

You can still have it like this

s=''
i=0
a={3:4,5:6}
for (k,v) in a.items():
    if i < len(a) and s == '':
        s = s + str(k) + ' '+ str(v)
    elif i < len(a) and s != '':
        s += ", " + str(k) + ' '+ str(v)
    i += 1
    print(s)

This should give you

s='3 4, 5 6'