How to change the field separator of a file using Python?
I'm new to Python from the R world, and I'm working on big text files, structured in data columns (this is LiDaR data, so generally 60 million + records).
Is it possible to change the field separator (eg from tab-delimited to comma-delimited) of such a big file without having to read the file and do a for loop on the lines?
Answer
No.
- Read the file in
- Change separators for each line
- Write each line back
This is easily doable with just a few lines of Python (not tested but the general approach works):
# Python - it's so readable, the code basically just writes itself ;-)
#
with open('infile') as infile:
with open('outfile', 'w') as outfile:
for line in infile:
fields = line.split('\t')
outfile.write(','.join(fields))
I'm not familiar with R, but if it has a library function for this it's probably doing exactly the same thing.
Note that this code only reads one line at a time from the file, so the file can be larger than the physical RAM - it's never wholly loaded in.