What does negative and positive value means in PCA final result?

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I am using PCA from sklearn for data reduction with 27 features and 3558 rows data and I got the following result

PCA result

I have read a lot of articles but they just explain the correlation between variables and each principal component (loadings), but here I want to know what does negative and positive value means in each cell (PC1 PC2 PC3) in each data row in the final result?

2 Answers

You can't really deduce much from the sign of a value in the principal components. Remember that the principal components are linear combinations of initial features. Thus, a negative component just means that a linear combination gave a negative number. For example you could have the first component equal to 5*feature_1-7*feature_2=x where x<0.

Not sure what you are trying to achieve here but if you want to understand more deeply what those components mean, I suggest to look at the code at the very bottom of this page.

Negative value means the component is not significant. Positive value means the component is significant.

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