Writing a dictionary data to a file?

[psbasha]

Hi,

I would like to write the dictionary data to the file.

The following stuff I am doing :

      sampleDict = { 100:[1,2,3],200:[4.5,6], 300:[7,8,9]}
      list1 = sampleDict.keys()
       sf =  open("C:\\TestFiles\\Sample.txt",'w')        
        for i in range( 0, list1.__len__()):
            f.write(sampleDict t[i])
            f.write('\n')            
        f.close()
 

I tried to get the size of the dictionary ( count = sampleDict.size),but it is giving error,so I am using list in between.
The out put should be

100 1 2 3
200 4 5 6
300 7 8 9

Could anybody help me in getting this output.

Thanks in advance
-PSB

[dshimer]

Using the exact same dictionary but calling it d and not getting too tricky.

>>> f=open(r'c:/tmp/test.txt','w')
>>> for i in d.keys():
...     f.write(repr(i))
...     for n in d[i]:
...         f.write(' %s'%(repr(n)))
...     f.write('\n')
... 
>>> f.close()

yields a file that looks like

200 4.5 6
300 7 8 9
100 1 2 3

[bartonc]

Hi,

I would like to write the dictionary data to the file.

The following stuff I am doing :

      sampleDict = { 100:[1,2,3],200:[4.5,6], 300:[7,8,9]}
      list1 = sampleDict.keys()
       sf =  open("C:\\TestFiles\\Sample.txt",'w')        
        for i in range( 0, list1.__len__()):
            f.write(sampleDict t[i])
            f.write('\n')            
        f.close()
 

I tried to get the size of the dictionary ( count = sampleDict.size),but it is giving error,so I am using list in between.
The out put should be

100 1 2 3
200 4 5 6
300 7 8 9

Could anybody help me in getting this output.

Thanks in advance
-PSB

As my friend dshimer points out, an extraction from the dictionary without the use of a sorted key list will result in arbitrary order of the result. And

 
        for i in range( 0, list1.__len__()):

should always be

 
        for i in range( 0, len(list1)):

or

 
        for i in range(len(list1)):

[bartonc]

If all you are trying to do is persist a dictionary over time, you may want to check out the cpickle library module. The old pickle module is implemented in python. The cpickle module is much faster. They both offer a simple way to store (semi) encoded python object to disk.

[dshimer]

I am missing something. It seems to me that the whole range on len is a mis-step. Originally I was trying to point out that by simply "for" looping over the key list you could easily output the items. In retrospect I should have

list1 = sampleDict.keys()
list1.sort()
for i in list1:

to sort the order, but now that I look at it, I don't understand the

f.write(sampleDict t[i])

line. What does that t[i] do?

[bartonc]

I am missing something. It seems to me that the whole range on len is a mis-step. Originally I was trying to point out that by simply "for" looping over the key list you could easily output the items. In retrospect I should have

list1 = sampleDict.keys()
list1.sort()
for i in list1:

to sort the order, but now that I look at it, I don't understand the

f.write(sampleDict t[i])

line. What does that t[i] do?

Yep. Your way is WAY better. I think that PSB was making a guess and all I was doing was pointing out improper use if internals method.

[bvdet]

I am missing something. It seems to me that the whole range on len is a mis-step. Originally I was trying to point out that by simply "for" looping over the key list you could easily output the items. In retrospect I should have

list1 = sampleDict.keys()
list1.sort()
for i in list1:

to sort the order, but now that I look at it, I don't understand the

f.write(sampleDict t[i])

line. What does that t[i] do?

I think he made a typo. It should be

f.write(sampleDict[i])

I have a version:

f = open("your_file",'w')
for key in sorted(dd):
    f.write('%s %s\n' % (str(key), ''.join(repr(dd[key]).strip('[]').split(','))))
f.close()

[joshbwhite]

I use this method to read and write a python dictionary to file.
>> d = {"names":['yar','har','gar'],"places":['far','near','mars']}
>> file('dict.txt','w').write(repr(a))

Then when I want it back on another run

>> r = file('dict.txt','r').read()
>> d = eval(r)

[aeneng]

@joshbwhite
This is very useful to store the dictionary.