Python convert string to float

Question

I have a string that looks like this:

a = "'92.345'\r\n\r\n"
a.strip()

When I try to convert it into float using np.float(a) or just float(a), I get

*** Value error: could not convert string to float: '92.345'

How do I convert it cleanly to a float?

What do you think would `\r` or `\n` become when converted to a float? — TidB, Mar 23 '15 at 20:15
It's probably worth noting that `a.strip()` on its own does nothing. You have to do something with the result, ex. `a = a.strip()` or `x = float(a.strip())` or whatever. — Kevin, Mar 23 '15 at 20:20
@Daniel, getting it from a netcdf file. Using the nco tools to read it. Invoking nco tool through subprocess call in windows — user308827, Mar 23 '15 at 20:27

Mazdak · Accepted Answer · 2015-03-23T20:25:31.440

7

You need to strip your string to remove the whitespaces and one quote ':

>>> float(a.strip().strip("'"))
92.345

Or as @Martijn Pieters says in comment you can use use a.strip("\r\n\t '") to reduce this to one strip call.

edited Mar 23 '15 at 20:25

answered Mar 23 '15 at 20:15

Mazdak

3

or use `a.strip("\r\n\t '")` to reduce this to *one* strip call. – Martijn Pieters Mar 23 '15 at 20:23

score 2 · Answer 2 · answered Mar 23 '15 at 20:29

2

You can also use str.translate:

print(float(a.translate(None,"\r\n'")))

answered Mar 23 '15 at 20:29

score 1 · Answer 3 · edited Mar 23 '15 at 20:20

1

Try slicing the string to extract only the digit part of it:

a = "'92.345'\r\n\r\n"
x = float(a[1:6])

edited Mar 23 '15 at 20:20

Mazdak

answered Mar 23 '15 at 20:16

NevDev

The only issue with this is it can't do it again and again, you need to know what you are slicing before hand. – Zizouz212 Mar 23 '15 at 20:17

score 1 · Answer 4 · answered Mar 23 '15 at 20:30

1

Remove everything but digit and dot

>>> a = "'92.345123'\r\n\r\n"
>>> float(re.sub(r'[^0-9\.]', '', a))
92.345123

answered Mar 23 '15 at 20:30

Heisenberg

4 Answers4