What is the most efficient way to delete a line from a string in python? I have tried
content = "first line \nsecond line\nthird line\netc.".splitlines()
i = 0
for line in iter(content):
if len(line) < 5:
content[i] = ""
i += 1
content = '\n'.join(content)
where my delete condition is just that the length of the line is smaller than 5 characters. Is there a more elegant/efficient way?
Here's a more concise one using a list comprehension:
'\n'.join([i if len(i) > 5 else '' for i in content.split('\n')])
#'first line \nsecond line\nthird line\n'
Now working from your approach... note that content is already an iterator, so there's no need for iter(content).
What else can be improved? Well instead of using a counter, python has a built-in function for that, enumerate. Using it your code could look like:
content = "first line \nsecond line\nthird line\netc."
content = content.splitlines()
for i, line in enumerate(content):
if len(line) < 5:
content[i] = ""
separator = '\n'
content = separator.join(content)
join is expecting a list, so it is actually somewhat faster when fed a list rather than a gen-comp @hansolo since it will construct a list anyway
else '' part. [i for i in content.split('\n') if len(i) > 5] would do
list is faster than gen-exporession for join. ApologiesAnother option is Python Regex:
import re
content = "first line \nsecond line\nthird line\netc."
print(re.sub(r'^.{1,5}$', '', content, flags=re.MULTILINE))
Resulting:
'first line \nsecond line\nthird line\n'
yatu's answer is nice and pythonic, but we can go further!
content = "first line \nsecond line\nthird line\netc."
content = '\n'.join(
i if len(i) > 5 else ''
for i in content.splitlines()
)
content
#'first line \nsecond line\nthird line'
str.join takes any iterable, so here use a generator expression for more pythonicness!
