Possible Duplicate:
Delete Chars in Python
I want to know how to delete strings after a keyword in python
I will get lines in a txt file
What method could I use to do this.
For example:
"I have a book to read."
I want to delete all words after "book".
To remove everything after the first "book" including "book" itself:
s = "I have a book to read."
print(s.partition("book")[0])
To preserve the word "book":
print(''.join(s.partition("book")[:2]))
Both work whether "book" present in the string or not.
Yet another way to do this is with re.sub. (Output is shown interleaved with code.)
txt = 'I have a book to read'; key='book'
str = re.sub(key+'.*', key, txt)
str
'I have a book'
txt = 'I have a look to read'; key='book'
str = re.sub(key+'.*', key, txt)
str
'I have a look to read'
There are several ways to do this:
mystr = "I have a book to read." keyword = 'book'
Method 1:
def foo(mystr, keyword):
try:
i = mystr.index(keyword)
return mystr[:i+len(keyword)]
except ValueError:
return mystr
Method 2:
def foo(mystr, keyword):
i = mystr.find(keyword)
if i >= 0:
return mystr[:i+len(keyword)]
else:
return mystr
Method 3:
def foo(mystr, keyword):
return ''.join(mystr.partition(keyword)[:2])
keyword is a variable, you might also want to use len(keyword) instead of 4
Use the stirng method find() which return the index of the first letter of the world:
str = "i have a book to read"
print str[:str.find("book") + len("book")]
This will work only because "book" exists in the string "i have a book to read". If this were not the case, this solution would not work as expected
'book' is not in the string. In that case, find returns -1 and you end up returning the first 3 characters of the input stringRegex would be good for this:
import re
m = re.match('(.*book)', line)
if m:
line = m.group(1)
or
line = re.sub('book.*', 'book', line)
