CODEWITHSUNDEEP
pythonlistfloating-pointtype-conversioninteger
Simplicity
Simplicity

Reputation: 48916

Converting a string to an integer or float

I have the following list:

[[1.01782362e-05 1.93798303e-04 7.96163586e-05 5.08812627e-06
  1.39600188e-05 3.94912873e-04 2.33748418e-04 1.22856018e-05]]

When I return its type, I get:

<class 'str'>

Is the reason for that the scientific notation used for instance (i.e. e-04)?

In this case, how can I convert the above list to an integer or float?

Thanks.

EDIT

The above list snippet comes from this CSV file under the "Feature" column.

Upvotes: 0

Views: 89

Answers (3)

Sam Mason
Sam Mason

Reputation: 16184

It looks a lot like you have NumPy's string representation of an array. As I linked above, there doesn't seem to be a nice way of parsing this back, but in your case it might not matter, Pandas and Numpy can sort of get there reasonably easily:

import pandas as pd
import numpy as np

# read in the data
df = pd.read_csv("features_thresholds.csv")

# use numpy to parse that column
df.Feature = df.Feature.apply(lambda x: np.fromstring(x[2:-2], sep=' '))

note that the x[2:-2] is trimming off the leading [[ and trailing ]], otherwise it's mostly standard Pandas usage that most data science tutorials will go through.

Upvotes: 1

saravanan saminathan
saravanan saminathan

Reputation: 702

We can use python ast (Abstract Syntax Tree) to process it efficiently

import ast
x = '[[1.01782362e-05 1.93798303e-04 7.96163586e-05 5.08812627e-06 1.39600188e-05 3.94912873e-04 2.33748418e-04 1.22856018e-05]]'
x = ast.literal_eval(x.replace(" ",","))
print(x)

Upvotes: 0

John Coleman
John Coleman

Reputation: 51998

What you posted must be part of a string literal:

s = '[[1.01782362e-05 1.93798303e-04 7.96163586e-05 5.08812627e-06 1.39600188e-05 3.94912873e-04 2.33748418e-04 1.22856018e-05]]'

In which case

list(map(float, s.lstrip('[').rstrip(']').split()))

evaluates to

[1.01782362e-05, 0.000193798303, 7.96163586e-05, 5.08812627e-06, 1.39600188e-05, 0.000394912873, 0.000233748418, 1.22856018e-05]

Upvotes: 0

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