[Solved] Reading every nth line into a column from txt file

[Yoriz]

output

Output:
CA50_40_ref_data2101_E04_spec0-70 #0
             Lifetimes (ns)   :    0.4000    0.1250    2.0446
             Std deviations   :     Fixed     Fixed    0.0339
             Intensities (%)  :   69.2721    9.6726   21.0553
             Std deviations   :    1.0359    0.8128    0.4063
Time-zero    Channel number   :   41.5603
             Std deviations   :    0.0588 
CA50_40_ref_data2101_E04_spec0-70 #1
             Lifetimes (ns)   :    0.4000    0.1250    2.0714
             Std deviations   :     Fixed     Fixed    0.0344
             Intensities (%)  :   70.0338    9.0952   20.8710
             Std deviations   :    1.0308    0.8135    0.4009
Time-zero    Channel number   :   41.5853
             Std deviations   :    0.0593
CA50_40_ref_data2101_E04_spec0-70 #2
             Lifetimes (ns)   :    0.4000    0.1250    2.0568
             Std deviations   :     Fixed     Fixed    0.0333
             Intensities (%)  :   69.5963    8.7445   21.6592
             Std deviations   :    1.0411    0.8177    0.4072
Time-zero    Channel number   :   41.5541
             Std deviations   :    0.0603
CA50_40_ref_data2101_E04_spec0-70 #3
             Lifetimes (ns)   :    0.4000    0.1250    2.0321
             Std deviations   :     Fixed     Fixed    0.0329
             Intensities (%)  :   70.4228    8.0614   21.5158
             Std deviations   :    1.0497    0.8219    0.4105
Time-zero    Channel number   :   41.4507
             Std deviations   :    0.0604
CA50_40_ref_data2101_E04_spec0-70 #4
             Lifetimes (ns)   :    0.4000    0.1250    2.0513
             Std deviations   :     Fixed     Fixed    0.0331
             Intensities (%)  :   67.2025   11.0731   21.7244
             Std deviations   :    1.0204    0.7976    0.4057
Time-zero    Channel number   :   41.6253
             Std deviations   :    0.0579

You may need to add some error checking

from itertools import zip_longest

HEADER = ('Dataset Lifetimes            Std deviations                    '
          'Intensities             Std deviations                    '
          'Time-zero Std deviation\n')


def grouper(iterable, n, fillvalue=''):
    "Collect data into fixed-length chunks or blocks"
    # grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx"
    args = [iter(iterable)] * n
    return zip_longest(*args, fillvalue=fillvalue)


class Dataset:
    def __init__(self, line: str) -> None:
        self.data = line.strip().split()[1]

    def __repr__(self) -> str:
        return f'{self.data:7}'


class LifeTimes:
    def __init__(self, line: str) -> None:
        self.data = line.strip().split()[3:6]

    def __repr__(self) -> str:
        return ' '.join(self.data)


class StdDeviations:
    def __init__(self, line: str) -> None:
        split_line = line.strip().split()
        self.data = [split_line[num] if split_line[num:]
                     else '' for num in range(3, 6)]

    def __repr__(self) -> str:
        return f"['{self.data[0]:^7}', '{self.data[1]:^7}', '{self.data[2]:^7}']"


class Intensities:
    def __init__(self, line: str) -> None:
        self.data = line.strip().split()[3:6]

    def __repr__(self) -> str:
        return f'{self.data[0]:>7} {self.data[1]:>7} {self.data[2]:>7}'


class TimeZero:
    def __init__(self, line: str) -> None:
        self.data = line.strip().split()[4]

    def __repr__(self) -> str:
        return f'{self.data:9}'


class Block:
    def __init__(self, dataset, lifetimes, std_deviations, intensities,
                 std_deviations2, time_zero, std_deviations3) -> None:
        self.dataset = Dataset(dataset)
        self.lifetimes = LifeTimes(lifetimes)
        self.std_deviations = StdDeviations(std_deviations)
        self.intensities = Intensities(intensities)
        self.std_deviations2 = StdDeviations(std_deviations2)
        self.time_zero = TimeZero(time_zero)
        self.std_deviations3 = StdDeviations(std_deviations3)

    def __repr__(self) -> str:
        return (f'{self.dataset} {self.lifetimes} {self.std_deviations}'
                f' {self.intensities} {self.std_deviations2}'
                f' {self.time_zero} {self.std_deviations3}\n')


with open('output') as file_in, open('out', 'w') as file_out:
    file_out.write(HEADER)
    for group in grouper(file_in, 7):
        file_out.write(str(Block(*group)))

out

Output:
Dataset Lifetimes            Std deviations                    Intensities             Std deviations                    Time-zero Std deviation
#0      0.4000 0.1250 2.0446 [' Fixed ', ' Fixed ', '0.0339 '] 69.2721  9.6726 21.0553 ['1.0359 ', '0.8128 ', '0.4063 '] 41.5603   ['0.0588 ', '       ', '       ']
#1      0.4000 0.1250 2.0714 [' Fixed ', ' Fixed ', '0.0344 '] 70.0338  9.0952 20.8710 ['1.0308 ', '0.8135 ', '0.4009 '] 41.5853   ['0.0593 ', '       ', '       ']
#2      0.4000 0.1250 2.0568 [' Fixed ', ' Fixed ', '0.0333 '] 69.5963  8.7445 21.6592 ['1.0411 ', '0.8177 ', '0.4072 '] 41.5541   ['0.0603 ', '       ', '       ']
#3      0.4000 0.1250 2.0321 [' Fixed ', ' Fixed ', '0.0329 '] 70.4228  8.0614 21.5158 ['1.0497 ', '0.8219 ', '0.4105 '] 41.4507   ['0.0604 ', '       ', '       ']
#4      0.4000 0.1250 2.0513 [' Fixed ', ' Fixed ', '0.0331 '] 67.2025 11.0731 21.7244 ['1.0204 ', '0.7976 ', '0.4057 '] 41.6253   ['0.0579 ', '       ', '       ']