How to read a txt file and create a dictionary with each key having list of values in python?

Question

I am reading a txt file, which is of the form:

in 0.01 -0.07 0.09 -0.02 0.27
and 0.2 0.3 0.5 0.6
to 0.87 0.98 0.54
from 1.2 5.4 0.2 0.4 

I want to create a dictionary such that each word is a key and its value is the list of numbers, like:

{in : [0.017077, -0.073018, 0.094730, -0.026420, 0.272884], and : [0.2, 0.3, 0.5 ,0.6]....}

How can I do that? Currently I'm doing something like:

with open('file.txt','r') as text:
    for line in text:
        key, value = line.split()
        res[key] = int(value)
print res

But it gives me error: too many values to unpack

Answer 1

line.split() returns a list of values, python can't tell how you'd want to split them between key and value , you need to be explicit about this

try:

vals = line.split()
key = vals[0]
value = [float(x) for x in vals[1:]]
res[key] = value

Answer 2

The problem is

key, value = line.split()

For example

>>> a = "in 0.01 -0.07 0.09 -0.02 0.27"
>>> a.split()
['in', '0.01', '-0.07', '0.09', '-0.02', '0.27']
>>> x, y = a.split()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: too many values to unpack

Split returns more than 2 values and your are trying to get those in 2 variables.

You can try

key , value = line.split()[0], line.split[1:]

Answer 3

You make two errors - the first is to unpack more than 2 values in two variables, the second is use int() casting to obtain float.

The simplest solution is like this using python 2.x:

res = dict()
with open('file.txt','r') as text:
    for line in text:
        record = line.split()
        key = record[0]
        values = [float(value) for value in record[1:]]
        res[key] = values
print res

Remember that in with python 3.x you can directly do this:

key, *values = line.split()

A more concise version use dictionary comprehension:

with open('file.txt','r') as text:
    res = {line.split()[0]: [v for v in map(float, line.split()[1:])] for line in text}