Finding the max value in a specific column-CodePudding

I am trying to find the max value under column "Climate change (kg CO2 eq.)" which is 1 but when I use scaled_df["Climate change (kg CO2 eq.)"].max() I get the answer to be 0.9999999999999999. How can I get the exact number?

Note: My dataset is very big, I've only provided a portion of it.

Part's Orientation (Support's volume) (cm^3)    Climate change (kg CO2 eq.) Climate change, incl biogenic carbon (kg CO2 eq.)   Fine Particulate Matter Formation (kg PM2.5 eq.)    Fossil depletion (kg oil eq.)   Freshwater Consumption (m^3)    Freshwater ecotoxicity (kg 1,4-DB eq.)  Freshwater Eutrophication (kg P eq.)    Human toxicity, cancer (kg 1,4-DB eq.)  Human toxicity, non-cancer (kg 1,4-DB eq.)  Ionizing Radiation (Bq. C-60 eq. to air)    Land use (Annual crop eq. yr)   Marine ecotoxicity (kg 1,4-DB eq.)  Marine Eutrophication (kg N eq.)    Metal depletion (kg Cu eq.) Photochemical Ozone Formation, Ecosystem (kg NOx eq.)   Photochemical Ozone Formation, Human Health (kg NOx eq.)    Stratospheric Ozone Depletion (kg CFC-11 eq.)   Terrestrial Acidification (kg SO2 eq.)  Terrestrial ecotoxicity (kg 1,4-DB eq.)
0   0.210866    0.040430    1.0 0.0 0.00    0.666667    0.040088    0.063802    0.040013    0.083205    0.005648    0.113808    0.104798    0.086400    0.108284    0.007368    0.091120    0.108676    0.090401    0.087426    0.101706    0.079028    0.080495    0.078380    0.082404    0.029502
1   0.210866    0.040430    1.0 0.2 0.00    0.666667    0.036597    0.038086    0.016068    0.074884    0.002636    0.045640    0.102285    0.082884    0.043371    0.003107    0.086700    0.105749    0.087161    0.084130    0.048885    0.072878    0.073529    0.074829    0.075438    0.011870
2   0.210866    0.044796    1.0 0.4 0.00    0.666667    0.031013    0.030436    0.008507    0.073035    0.001883    0.023401    0.102914    0.082494    0.022264    0.001854    0.086279    0.105749    0.086937    0.084130    0.032152    0.071341    0.071981    0.074698    0.073447    0.006456
3   0.210866    0.044311    1.0 0.6 0.00    0.666667    0.031013    0.026693    0.004883    0.072111    0.001506    0.012936    0.102914    0.082103    0.012289    0.001103    0.086069    0.105423    0.086602    0.084130    0.023950    0.070572    0.071207    0.074435    0.072452    0.003748
4   0.210866    0.045281    1.0 1.0 0.00    0.666667    0.031711    0.023438    0.001260    0.071803    0.001883    0.002180    0.103542    0.082884    0.002024    0.000601    0.086490    0.106074    0.087049    0.084542    0.015748    0.070572    0.071207    0.074961    0.072452    0.001249

CodePudding user response：

How can I get the exact number?

That is the exact number, it is completely accurate.

Suppose you had three observations of one-tenth. You apparently performed a computation like this:

scale_factor = (.1   .1   .1) / .3

with the expectation that it would result in 1.0.

But the FP quantity .1, with 24 bits of significand, is quite different from the rational number 1 divided by 10. It is impossible to represent the repeating digits (repeating bits, similar to repeating decimals) in a finite mantissa, so IEEE-754 computations are not going to give the result you hoped for.

Let's try it in python:

>>> (.1   .1   .1) / .3
1.0000000000000002
>>>

Is that result "wrong"? No. The machine correctly computed exactly what we asked for.

It sounds like you have a requirement for calling .round( ... ) on the results you compute.