CODEWITHSUNDEEP
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Felix Liu
Felix Liu

Reputation: 21

Finding index values where a Series value changes significantly

I have a data frame read from a csv log file. One of the columns that I am studying is Fan Speed. There were several fan speed step changes during the log. I want to automatically find the last index of each Fan Speed Change Step for the entire log. How should I approach this ? I am new to python. Some guidance are appreciated !

Regardsenter image description here

ffl3883

Upvotes: 1

Views: 249

Answers (1)

NicholasM
NicholasM

Reputation: 4673

You can get a series of changes in Series values using Series.diff(). Then, you could compare the absolute value of those changes to some tolerance that you choose.

STEP_CHANGE_TOLERANCE = 2500
idx = df[df["SYS_FAN_0_0"].diff().abs() > STEP_CHANGE_TOLERANCE].index

The code above will give the first (I think) index value of each new speed. If you want the last index of each region, you could try:

idx_fwd = df[df["SYS_FAN_0_0"].diff(-1).abs() > STEP_CHANGE_TOLERANCE].index

Upvotes: 1

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