Cast list of string to different data type in python

Question

I was wondering if there is a cleaner way to parse the following string:

line = "NOVEL_SERIES, 3256432, 8, 1, 2.364, 4.5404, 9.8341"
key, id, xval, yval, est1, est2, est3 = line.split()
id   = int(id)
xval = int(value1)
yval = int(value2)
est1 = float(est1)
est2 = float(est2)
est3 = float(est3)

Also you probably mean xval = int(xval) and yval = int(yval) — ml-moron
– ml-moron, Commented Feb 26, 2016 at 16:34

B. M. · Accepted Answer · 2016-02-26 16:38:05Z

6

Perhaps a bit more readable by expliciting converters :

In [29]: types=[str,int,int,int,float,float]

In [30]: [f(x) for (f,x) in zip(types,line.split(', '))]
Out[30]: ['NOVEL_SERIES', 3256432, 8, 1, 2.364, 4.5404]

answered Feb 26, 2016 at 16:38

B. M.

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4 Comments

idjaw Over a year ago

Wow...that's a really interesting approach. Good job!

CG Nguyen Over a year ago

I have a question, since I am new to Python and just try to understand: why both x('10.9') and float('10.9') return the same value? >>> x <type 'float'> >>> x('10.9') 10.9 >>> float(10.9) 10.9

B. M. Over a year ago

I don't understand whats is x here ?

CG Nguyen Over a year ago

B.M. please see the better format question I just added bellow

Community · Accepted Answer · 2017-05-23 11:45:08Z

5

You can use numpy.genfromtxt() to automatically detect data types (inspired by this answer) - specify the dtype as None and set the appropriate delimiter:

>>> import numpy as np
>>> from StringIO import StringIO
>>>
>>> buffer = StringIO(line)
>>> key, id, xval, yval, est1, est2, est3 = np.genfromtxt(buffer, dtype=None, delimiter=", ").tolist()
>>> key
'NOVEL_SERIES'
>>> id
3256432
>>> xval
8
>>> yval
1
>>> est1
2.364
>>> est2
4.5404
>>> est3
9.8341

edited May 23, 2017 at 11:45

CommunityBot

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answered Feb 26, 2016 at 16:33

alecxe

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1 Comment

alecxe Over a year ago

@idjaw definitely, same here, but we should always remember that "explicit is better than implicit" too.

gkusner · Accepted Answer · 2016-02-26 17:07:16Z

0

you can build on B.M. s answer to get ALL the fields and name them:

line = "NOVEL_SERIES, 3256432, 8, 1, 2.364, 4.5404, 9.8341"
types=[str,int,int,int,float,float,float]
key, id, xval, yval, est1, est2, est3 = [f(x) for (f,x) in zip(types,line.split(', '))]

>>> [key, id, xval, yval, est1, est2, est3]
['NOVEL_SERIES', 3256432, 8, 1, 2.364, 4.5404, 9.8341]
>>> key
'NOVEL_SERIES'

answered Feb 26, 2016 at 17:07

gkusner

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