Assigning cycle values in a list

[deanhystad]

Can you provide sample input and desired output?

Are time sequence numbers always consecutive in a segment? If so, you could use the shift command to find numbers out of sequence.

import pandas as pd

# Make some data
df = pd.DataFrame({"time":[-2, -1, 0, 1, -1, 0, 1, 0, 1, 2, 3]})

# Make new series that is the time series data down 1 row + 1.  As long as numbers in time
# are sequential, time == shifted time.  Set first value in shifted time to something that won't
# match anything in time.
df["shifted"] = (df.time.shift(1, fill_value=0.5) + 1)

# Find where time != shifted time.  This is the start of a series.
df["mismatch"] = df.time != df.shifted

# Count the mismatches.  This is the series number.
df["series"] = df.mismatch.cumsum()
print(df)

Output:
    time  shifted  mismatch  series
0     -2      1.5      True       1
1     -1     -1.0     False       1
2      0      0.0     False       1
3      1      1.0     False       1
4     -1      2.0      True       2
5      0      0.0     False       2
6      1      1.0     False       2
7      0      2.0      True       3
8      1      1.0     False       3
9      2      2.0     False       3
10     3      3.0     False       3

Doing it all in one line.

import pandas as pd

df = pd.DataFrame({"time":[-2, -1, 0, 1, -1, 0, 1, 0, 1, 2, 3]})
df["series"] = (df.time != (df.time.shift(1, fill_value=0.5) + 1)).cumsum()
print(df)

Output:
    time  series
0     -2       1
1     -1       1
2      0       1
3      1       1
4     -1       2
5      0       2
6      1       2
7      0       3
8      1       3
9      2       3
10     3       3