change a text file to a dictionary

[zirkon]

I have a text file, which contains a list of element and their weight, and i need to split the list up and sort it by the weight of the elements. So i need
to change the weight to a float.

The text file:
Ac 227.0
Ag 107.868
Al 26.98154
Am 241.1
Ar 39.948
As 74.9216
...

So far i have done this:

# ----The data structure----
# The input file
text_file=open("avikt.txt","r")  
Lines = text_file.readlines()    
text_file.close()
# The Lines get broken into columns and in 1 list "Element"
Element = map(string.split,Lines) # now Element is a nested list ...
                                              # [['Ac','227.0'],['Ag','107.868'],...

# The problem now is to change the atom weight into a float
# to sort it.

# I make the Element list into a dictionary
# where the Atom is the key and the atom weight
# is the value
d  = dict(Element)

# now i have to sort the dictionary by the value, or the atom weight
items = [(v,k) for k, v in d.items()]
items.sort()
items = [(k,v) for v, k in items]

Can anybody help me??

[bartonc]

Hey, guys...

This is an old post, but has been viewed over 500 times.
That's over 500 people looking for an answer, and if they had found one, may have joined the forum. I'll dig up old posts from time to time just for this reason.

I have a text file, which contains a list of element and their weight, and i need to split the list up and sort it by the weight of the elements. So i need
to change the weight to a float.

The text file:
Ac 227.0
Ag 107.868
Al 26.98154
Am 241.1
Ar 39.948
As 74.9216
...

So far i have done this:

# ----The data structure----
# The input file
text_file=open("avikt.txt","r")  
Lines = text_file.readlines()    
text_file.close()
# The Lines get broken into columns and in 1 list "Element"
Element = map(string.split, Lines) # now Element is a nested list ...
                                              # [['Ac','227.0'],['Ag','107.868'],...

# The problem now is to change the atom weight into a float
# to sort it.

# I make the Element list into a dictionary
# where the Atom is the key and the atom weight
# is the value
d  = dict(Element)

# now i have to sort the dictionary by the value, or the atom weight
items = [(v,k) for k, v in d.items()]
items.sort()
items = [(k,v) for v, k in items]

Can anybody help me??

Sorting a dictionary doesn't work (they are not ordered lists). The use of map() is quite good though.

[ghostdog74]

one example, although the format of the float values may not be what OP wants

import operator
data = open("file").readlines()
data = [i.split() for i in data]
data = [ [k[0],float(k[1]) ] for k in data]
data = sorted(data, key=operator.itemgetter(1)) #sort by 2nd element
data = [ [j[0],"%.5f" % j[1]]  for j in data]
print data

output

[['Al', '26.98154'], ['Ar', '39.94800'], ['As', '74.92160'], ['Ag', '107.86800'], ['Ac', '227.00000'], ['Am', '241.10000']]

[bartonc]

one example, although the format of the float values may not be what OP wants

import operator
data = open("file").readlines()
data = [i.split() for i in data]
data = [ [k[0],float(k[1]) ] for k in data]
data = sorted(data, key=operator.itemgetter(1)) #sort by 2nd element
data = [ [j[0],"%.5f" % j[1]]  for j in data]
print data

output

[['Al', '26.98154'], ['Ar', '39.94800'], ['As', '74.92160'], ['Ag', '107.86800'], ['Ac', '227.00000'], ['Am', '241.10000']]

You are THE MAN, GD. It makes me wish that I weren't so busy creating GUI apps. I'd love to know the Global Module Index the way that you do (I've never even looked at the operator module before).

Thanks!

[ghostdog74]

hi, if you are interested, here's the documentedlink that i got it from.

[bvdet]

Nice solution ghostdog74. Like Barton, I am not very familar with the operator module other than to access new division (operator.trued iv()). For the exercise, here's another approach:

data = [item.split() for item in open('file_name').readlines()]
dataDict = dict(zip([float(i[1]) for i in data], [j[0] for j in data]))
print dataDict

outList = [[dataDict[key], '%01.5f' % key] for key in sorted(dataDict.keys())]
print outList

'''
>>> {39.948: 'Ar', 227.0: 'Ac', 241.09999999999999: 'Am', 26.981539999999999: 'Al', 74.921599999999998: 'As', 107.86799999999999: 'Ag'}
[['Al', '26.98154'], ['Ar', '39.94800'], ['As', '74.92160'], ['Ag', '107.86800'], ['Ac', '227.00000'], ['Am', '241.10000']]
>>> 
'''

I looked up operator.itemge tter(item):
'Creates a callable object, f, where a call to f(obj) returns obj[item].'