maybe there are enough questions and/or solutions for this, but I just can't help myself with this one question: I've got the following command I'm using in a bash-script:
var=$(cat "$filename" | grep "something" | cut -d'"' -f2)
Now, because of some issues I have to translate all the code to python. I never used python before and I have absolutely no idea how I can do what the postet commands do. Any ideas how to solve that with python?
You need to have better understanding of the python language and its standard library to translate the expression
cat "$filename": Reads the file cat "$filename" and dumps the content to stdout
|: pipe redirects the stdout from previous command and feeds it to the stdin of the next command
grep "something": Searches the regular expressionsomething plain text data file (if specified) or in the stdin and returns the matching lines.
cut -d'"' -f2: Splits the string with the specific delimiter and indexes/splices particular fields from the resultant list
Python Equivalent
cat "$filename" | with open("$filename",'r') as fin: | Read the file Sequentially
| for line in fin: |
-----------------------------------------------------------------------------------
grep 'something' | import re | The python version returns
| line = re.findall(r'something', line)[0] | a list of matches. We are only
| | interested in the zero group
-----------------------------------------------------------------------------------
cut -d'"' -f2 | line = line.split('"')[1] | Splits the string and selects
| | the second field (which is
| | index 1 in python)
import re
with open("filename") as origin_file:
for line in origin_file:
line = re.findall(r'something', line)
if line:
line = line[0].split('"')[1]
print line