Access part of data using a function?

Question

I have a lot of data form which I want to feed floating points into some other function. To do this, I have created a function Lsym(s,n,N = '11a') which does the job for me partially. I want to access the floating points on the right-hand side of the data below

Lsym['11a'][1][2]=1.057599244591
Lsym['11a'][2][2]=1.127354242069
Lsym['11a'][3][2]=1.090644807038
Lsym['11a'][4][2]=1.052410518255
Lsym['11a'][5][2]=1.02815187087
Lsym['11a'][2][4]=0.8209366139554
Lsym['11a'][3][4]=0.8949278089063
Lsym['11a'][4][4]=0.9429984866328
Lsym['11a'][5][4]=0.970256549013
Lsym['11a'][3][6]=0.8929614099822
Lsym['11a'][4][6]=0.9434221639356
Lsym['11a'][5][6]=0.970721596782
Lsym['11a'][4][8]=1.053427474878
Lsym['11a'][5][8]=1.02816330898    
Lsym['11a'][5][10]=1.03597753138
.....

The code I have written is

def Lsym(s,n,N = '11a'):
    f = open("path",'r')
    for item in f:
        if item.split('=')[0][6:-8] == N:
            if s == int(item.split('=')[0][-5]):
                if n == int(item.split('=')[0][-2]): 
                    id1 = float(item.split('=')[1][:-1])
               if n == int(item.split('=')[0][15:17]):
                   id1 = float(item.split('=')[1][:-1])
    return id1

The output of this is

sage: Lsym(1,2)
sage: 1.057599244591
sage: Lsym(3,6)
sage: 0.8929614099822

However when I call

sage: Lsym(5,10)
ValueError: invalid literal for int() with base 10: '2]'

How do I fix this? Or is there any better way to access those float Values? In particular, how do I access

Lsym(5,10)?

Thanks for time and help.

Answer 1

Here a solution that works also with numbers greater than 9 for s and n.

def Lsym(s,n,N = '11a'):
    with open("path",'r') as f:
        for item in f:
            [head,number] = item.split("=")
            [_, first,second,third] = head.replace('[',' ').replace(']',' ').split()
            if first.strip('\'') == N and int(second) == s and int(third) == n:
                return number.strip()

Answer 2

The problem you have is that you use positional indexing into a string. So, when you go to two digits ('10'), your selection goes wrong

One quick fix to split again on "["

def Lsym(s,n,N = '11a'):
    f = open("path",'r')
    for item in f:
        if item.split('=')[0].split('[')[1][1:-2] == N:
            if s == int(item.split('=')[0].split('[')[2][:-1]):
                if n == int(item.split('=')[0].split('[')[3][:-1]): 
                    id1 = float(item.split('=')[1][:-1])
    return id1