Python

String Split in Python

Thread Solved

•

Join Date: Jun 2009

Posts: 13

Reputation: kes_ee is an unknown quantity at this point

Solved Threads: 0

kes_ee

Offline

Newbie Poster

String Split in Python

Jul 1st, 2009

I am having a text file contaning the following:
"int Function1 (int arg1, "0|1", char * arg2);
int Function2 (int arg1, " ", char * prt1);
..."
I need to open this file, split the each word and store it as global variable. I did this in Perl but now I need it in Python. I am new to Python. Give some idea to acheive this in Python.

•

Join Date: Jul 2007

Posts: 495

Reputation: shadwickman will become famous soon enough

Solved Threads: 76

shadwickman shadwickman is offline

Offline

Posting Pro in Training

Re: String Split in Python

Jul 1st, 2009

If by each "word", you mean strictly at every space, then you could read the file line by line, and perform this on every line:

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
fh = open('filename', 'r')
for line in fh.readlines():
    # use 'xreadlines()' if the file is large and you just want an iterator
    words = line.split(' ')
    # returns an array of every item between the spaces
    # do something else...
fh.close()
fh = open('filename', 'r')
for line in fh.readlines():
    # use 'xreadlines()' if the file is large and you just want an iterator
    words = line.split(' ')
    # returns an array of every item between the spaces
    # do something else...
fh.close()

The 'words' list would look like this on the first line in that file:

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
['int', 'Function1', '(int', 'arg1,', '"0|1",', 'char', '*', 'arg2);']
['int', 'Function1', '(int', 'arg1,', '"0|1",', 'char', '*', 'arg2);']

Notice that some indices still have the commas, brackets, etc in them because they didn't have spaces in between. Is this ok or did you mean "words" as in a list of the function type, name, and the arguments not broken up like split(' ') did? Give an example of what you want the split-up line's list to look like.

Last edited by shadwickman; Jul 1st, 2009 at 2:56 am.

"Two good old boys in a fire-apple red convertible. Stoned. Ripped. Twisted. Good people."
- Hunter S. Thompson

•

Join Date: Jun 2009

Posts: 13

Reputation: kes_ee is an unknown quantity at this point

Solved Threads: 0

kes_ee

Offline

Newbie Poster

Re: String Split in Python

Jul 1st, 2009

I need to take somthing like,
int, Function1, int arg1, 0|1, char * arg2 ... etc.
and similarly I need to do the same for all the lines in file and store it in somthing like global array. This varaibles will be used in some other function.

Thanks.

•

Join Date: Jul 2007

Posts: 495

Reputation: shadwickman will become famous soon enough

Solved Threads: 76

shadwickman shadwickman is offline

Offline

Posting Pro in Training

Re: String Split in Python

Jul 1st, 2009

You can incorporate this easily into your script as a function, etc.

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
# split at the first bracket - the function, and the arguments
func, args = f.split("(")
# split the function into its type and name
func = func.split(" ")
# split the arguments at each comma
args = args.split(",")
# get rid of ending bracket and semicolon from last arg
args[-1] = args[-1][:2]
# put both lists together
result = func + args
#strip any leading or trailing whitespace from the items
result = [item.strip() for item in result]
# remove any list indices that are blank strings
result = filter(lambda x: x != "", result)
 
""" my result on the first line in your file:
['int', 'Function1', 'int arg1', '"0|1"', 'char * arg2']
"""
# split at the first bracket - the function, and the arguments
func, args = f.split("(")
# split the function into its type and name
func = func.split(" ")
# split the arguments at each comma
args = args.split(",")
# get rid of ending bracket and semicolon from last arg
args[-1] = args[-1][:2]
# put both lists together
result = func + args
#strip any leading or trailing whitespace from the items
result = [item.strip() for item in result]
# remove any list indices that are blank strings
result = filter(lambda x: x != "", result)

""" my result on the first line in your file:
['int', 'Function1', 'int arg1', '"0|1"', 'char * arg2']
"""

That's pretty well commented for you to understand. The last little strip() part is because when split at a comma, the following argument would start with a space. By calling strip() on all the resulting items, we ensure that none of them have excess leading or trailing whitespace. And when we split the func list at any spaces (to get the type and name), the space right after the name (before the bracket originally) made a blank index, so later on I added that filter call to weed out any blank-string indices. Tell me if you need any other clarification.
Hope that helps!

Last edited by shadwickman; Jul 1st, 2009 at 5:11 am.

"Two good old boys in a fire-apple red convertible. Stoned. Ripped. Twisted. Good people."
- Hunter S. Thompson

•

Join Date: Jun 2009

Posts: 13

Reputation: kes_ee is an unknown quantity at this point

Solved Threads: 0

kes_ee

Offline

Newbie Poster

Re: String Split in Python

Jul 1st, 2009

•

Originally Posted by shadwickman

You can incorporate this easily into your script as a function, etc.
Help with Code Tags

python Syntax (Toggle Plain Text)
# split at the first bracket - the function, and the arguments
func, args = f.split("(")
# split the function into its type and name
func = func.split(" ")
# split the arguments at each comma
args = args.split(",")
# get rid of ending bracket and semicolon from last arg
args[-1] = args[-1][:2]
# put both lists together
result = func + args
#strip any leading or trailing whitespace from the items
result = [item.strip() for item in result]
# remove any list indices that are blank strings
result = filter(lambda x: x != "", result)
 
""" my result on the first line in your file:
['int', 'Function1', 'int arg1', '"0|1"', 'char * arg2']
"""
# split at the first bracket - the function, and the arguments func, args = f.split("(") # split the function into its type and name func = func.split(" ") # split the arguments at each comma args = args.split(",") # get rid of ending bracket and semicolon from last arg args[-1] = args[-1][:2] # put both lists together result = func + args #strip any leading or trailing whitespace from the items result = [item.strip() for item in result] # remove any list indices that are blank strings result = filter(lambda x: x != "", result) """ my result on the first line in your file: ['int', 'Function1', 'int arg1', '"0|1"', 'char * arg2'] """
That's pretty well commented for you to understand. The last little strip() part is because when split at a comma, the following argument would start with a space. By calling strip() on all the resulting items, we ensure that none of them have excess leading or trailing whitespace. And when we split the func list at any spaces (to get the type and name), the space right after the name (before the bracket originally) made a blank index, so later on I added that filter call to weed out any blank-string indices. Tell me if you need any other clarification.
Hope that helps!

Hi,

Thank you very much for your effort and It is working for me.
And one more thing, Can I find the number of flower brackets "()" and square brackets "[]" from the following line:

•

Function1 (text1) (text2) (text3) [text4]

Thanks.

•

Join Date: Mar 2007

Posts: 1,597

Reputation: Lardmeister is an unknown quantity at this point

Solved Threads: 28

Lardmeister Lardmeister is offline

Offline

Posting Virtuoso

Re: String Split in Python

Jul 1st, 2009

Use something like this:

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
s = "Function1 (text1) (text2) (text3) [text4]"
 
print s.count('(')
print s.count(')')
print s.count('[')
print s.count(']')
s = "Function1 (text1) (text2) (text3) [text4]"

print s.count('(')
print s.count(')')
print s.count('[')
print s.count(']')