熊猫数据框浮点精度

Question

I am trying to alter my dataframe with the following line of code:

 df = df[df['P'] <= cutoff]

However, if for example I set cutoff to be 0.1, numbers such as 0.100496 make it through the filter.

My suspicion is that my initial dataframe has entries in scientific notation and float format as well. Could this be affecting the rounding and precision? Is there a potential workaround to this issue.

Thank you in advance.

EDIT: I am reading from a file. Here is a sample of the total data.

2.29E-98
1.81E-42
2.19E-35
3.35E-30
0.0313755
0.0313817
0.03139
0.0313991
0.0314062
0.1003476
0.1003483
0.1003487
0.1003521 
0.100496

Answer 1

Floating point comparison isn't perfect. For example

>>> 0.10000000000000000000000000000000000001 <= 0.1
True

Have a look at numpy.isclose . It allows you to compare floats and set a tolerance for the comparison.

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