Loading UTF-8 file in Python 3 using numpy.genfromtxt
Solution 1:
Note the original 2015 date. Since then genfromtxt
has gotten an encoding
parameter.
In Python3 I can do:
In [224]: txt = "Côte d'Ivoire"
In [225]: x = np.zeros((2,),dtype='U20')
In [226]: x[0] = txt
In [227]: x
Out[227]:
array(["Côte d'Ivoire", ''], dtype='<U20')
Which means I probably could open a 'UTF-8' file (regular, not byte mode), and readlines, and assign them to elements of an array like x
.
But genfromtxt
insists on operating with byte strings (ascii) which can't handle the larger UTF-8
set (7 bytes v 8). So I need to apply decode
at some point to get an U
array.
I can load it into a 'S' array with genfromtxt
:
In [258]: txt="Côte d'Ivoire"
In [259]: a=np.genfromtxt([txt.encode()],delimiter=',',dtype='S20')
In [260]: a
Out[260]:
array(b"C\xc3\xb4te d'Ivoire", dtype='|S20')
and apply decode
to individual elements:
In [261]: print(a.item().decode())
Côte d'Ivoire
In [325]: print _
Côte d'Ivoire
Or use np.char.decode
to apply it to each element of an array:
In [263]: np.char.decode(a)
Out[263]:
array("Côte d'Ivoire", dtype='<U13')
In [264]: print(_)
Côte d'Ivoire
genfromtxt
lets me specify converters
:
In [297]: np.genfromtxt([txt.encode()],delimiter=',',dtype='U20',
converters={0:lambda x: x.decode()})
Out[297]:
array("Côte d'Ivoire", dtype='<U20')
If the csv
has a mix of strings and numbers, this converters
approach will be easier to use than the np.char.decode
. Just specify the converter for each string column.
(See my earlier edits for Python2 tries).