Reading the First N Lines of a Text File
Problem:
Trimming large raw data files to a specified size requires reading the first N lines of a text file. Understanding the impact of the operating system on this implementation is crucial.
Implementation in Python:
Both Python 2 and 3 provide efficient methods for reading the first N lines of a text file using the with statement:
with open(path_to_file) as input_file:</p> <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">head = [next(input_file) for _ in range(lines_number)]
print(head)
Alternatively, itertools.islice provides another solution:
from itertools import islice</p> <p>with open(path_to_file) as input_file:</p> <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">head = list(islice(input_file, lines_number))
print(head)
Operating System Impact:
The underlying OS does not influence the implementation of these methods significantly.
Additional Notes:
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