After converting 'xlsx' file to 'nc' format, an error keeps popping up while saving.

>>> float("1")
1.0
>>> float("2.33")
2.33
>>> s = 1
>>> float(s)
1.0
>>> s = 3.3
>>> float(s)
3.3
>>> s = "One"
>>> float(s)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: could not convert string to float: 'One'
>>>