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Processing CSV files with csv.DictReader is great - but I have CSV files with comment lines (indicated by a hash at the start of a line), for example:
# step size=1.61853 val0,val1,val2,hybridisation,temp,smattr 0.206895,0.797923,0.202077,0.631199,0.368801,0.311052,0.688948,0.597237,0.402763 -169.32,1,1.61853,2.04069e-92,1,0.000906546,0.999093,0.241356,0.758644,0.202382 # adaptation finished The csv module doesn't include any way to skip such lines.
I could easily do something hacky, but I imagine there's a nice way to wrap a csv.DictReader around some other iterator object, which preprocesses to discard the lines.
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A naive way to read a file and skip initial comment lines is to use “if” statement and check if each line starts with the comment character “#”. Python string has a nice method “startswith” to check if a string, in this case a line, starts with specific characters. For example, “#comment”.startswith (“#”) will return TRUE.
A naive way to read a file and skip initial comment lines is to use “if” statement and check if each line starts with the comment character “#”. Python string has a nice method “startswith” to check if a string, in this case a line, starts with specific characters.
Python does not really have a syntax for multi line comments. To add a multiline comment you could insert a # for each line:
The initial few lines of the text file that you want to skip are typically comment or some meta data and starts with some special characters like “#”. Here are 3 ways to read a text file line by line Python and skip initial comment lines. You don’t have to know how many lines you want to skip.
Actually this works nicely with filter:
import csv fp = open('samples.csv') rdr = csv.DictReader(filter(lambda row: row[0]!='#', fp)) for row in rdr: print(row) fp.close() If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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