When reading CSV, float-like strings lacking exponent digits are accepted as floats · Issue #12237 · pandas-dev/pandas (original) (raw)

The data-frame

DataFrame({'x': [2.5], 'y': [42], 'z': ['2E']})

does not round-trip correctly via CSV. The string '2E' is interpreted as a valid float, but it should not be (according to man strtod(3), which seems a reasonable spec).