How get row index of matching row in column 0

[perfringo]

One way is to take advantage of iterator protocol. This is based on list, but file objects are also iterable and therefore might give some ideas.

s = ['inter value,70',
     'time interval[min],20',               
     'dose_trigger value,-23',              
     'warning_linit1,36',               
     'warning limit2,15',               
     'cooling time [hrs],2',                
     'cooling number[#],30',                
     'Trail_number,initila,final,middle,max,min',
     'Trial_20157832,1,23,14,28,1',
     'Standard,0,5,2.6,5,0',
     'Trial_20037924, 2,13,17,20,0',
     'Trial_20637924,6,18,19,17,3']

first = list()
second = list()

rows = iter(s)                          # create iterator

for row in rows:
    if row.startswith('Trail_number'):  # consume iterator until sentinel and break
        second.append(row)
        break
    else:
        first.append(row)

for row in rows:                         # consume remaining iterator
    second.append(row)

# first
['inter value,70',
 'time interval[min],20',
 'dose_trigger value,-23',
 'warning_linit1,36',
 'warning limit2,15',
 'cooling time [hrs],2',
 'cooling number[#],30']

# second
['Trail_number,initila,final,middle,max,min',
 'Trial_20157832,1,23,14,28,1',
 'Standard,0,5,2.6,5,0',
 'Trial_20037924, 2,13,17,20,0',
 'Trial_20637924,6,18,19,17,3']