[ Pulling text from file with python ]
I have a text file that I am opening in my python code. I want to search through the file and pull out the text that is followed by a specific symbol. For instance my text file name File.txt is:
Hello, this is just a dummy file that has information with no substance at all and I want to pull the information between the dollar sign symbols. So all of this $ in between here should be pulled out so I can do what ever I want to with it $ and the rest of this will be a second group.
Here is a sample of my code:
class FileExtract(object):
__init__(self):
pass
def extractFile(self):
file = open(File.txt)
wholeFile = file.read()
file.close()
symCount = wholefile.count("$")
count = 0 #Will count the each $ as it finds it
begin = False #determines which the $ has been found and begin to start copying word
myWant = [] #will add the portion I want
for word in wholeFile.split():
while(count != symCount):
if word != "$" and begin == False:
break
if word == "$" and begin == False:
myWant.append(word)
begin = True
count = count + 1 #it found one of the total symbols
break
elif word != "$" and begin == True:
myWant.append(word)
break
elif word == "$" and begin == True:
begin = False
break
print myWant
I would like for it to print:
"$ in between here should be pulled out so I can do what ever I want to with it"
"$ and the rest of this will be a second group."
This is the only way I can think to pull the text out (which I know is horrible, please take it easy Im just learning). The problem is that my way is putting it into a list and I would like for it to just print the string out with spaces, newlines, and all. Any suggestions or other build in functions/methods that I am overlooking that would help me?
Answer 1
s = "Hello, this is just a dummy file that has information with no substance at all and I want to pull the information between the dollar sign symbols. So all of this $ in between here should be pulled out so I can do what ever I want to with it $ and the rest of this will be a second group."
a = s.split("$")[1:]
print a
Of course, the delimiter won't be in the results, but it'd be trivial to append that yourself.
Answer 2
Well, you could do wholefile.split('$')
and then have 3 element list: what's before the first $, the stuff between the $'s, and the stuff after the second $. (and no $'s.)
Or even print '\n$'.join(wholefile.split('$'))
And as a minimal function:
def extract_file(filename):
return '\n$'.join(open(filename).read().split('$'))
Answer 3
This is what flex is for. You don't need to use flex to do the same thing in python though.
firstFlag = False
secondFlag = False
outputFile1 = open('first.txt', 'wb')
outputFile2 = open('second.txt', 'wb')
yourFile = open('thefile.txt', 'rb')
while True:
char = yourFile.read(1)
if not char:
break
if char == '$'
if firstFlag:
secondFlag = True
firstFlag = True
if firstFlag and not secondFlag:
outputFile1.write(data)
elif secondFlag:
outputFile2.write(data)
Since this isn't native C code, it won't be exactly fast. I'd suggest you take a look at flex not just for the handy tool, but also for the learning experience.
The above code in flex:
%option 8bit outfile="scanner.c"
%option nounput nomain noyywrap
%option warn
%x First
%x Second
%%
. { ECHO; }
\$ { BEGIN First; yyout = fopen("first.txt", "wb"); }
<First>\$ { BEGIN Second; fclose(yyout); yyout = fopen("second.txt", "wb");}
<First>. { ECHO; }
<Second>. { ECHO; }
%%
The dot commands send each character to yyout, which starts pointing to stdout. To compile this:
flex -Cf scanner.l
gcc -O -o flexer.exe scanner.c
It will take it's input from stdin.
Answer 4
It's actually quite simple. Without using split nor storing the results in a list:
def extractFile(self):
file = open(File.txt)
wholeFile = file.read()
file.close()
pos = wholeFile.find("$")
while pos > 0:
pos2 = wholeFile.find("$")
if pos2 > 0:
print wholeFile[pos:pos2]
else:
print wholeFile[pos:]
pos = pos2