[Tutor] how to split/partition a string on keywords?
Hi all,
I'm new to programming and Python.
I want to write a script that takes a string input and breaks the string at
keywords then outputs the pieces on separate lines.
I'm not sure how to break the string, though.
I looked through the docs and found split() and partition(), which come
close.
But split() doesn't retain the separator and partition() retains the white
space and returns a 3-tuple which I'll have to figure out how to rejoin nor
does it partition on subsequent instances of the separator.
Here's the script in its basic form:
#!/usr/bin/python
text = raw_input("Enter text: ")
print "You entered ", text
objects = text.partition(' and')
print objects
for object in objects:# Second Example
print object
For example, if I run this with the input:
"Ham and cheese omelette with hasbrowns and coffee."
I get:
Ham
and
cheese omelette with hashbrowns and coffee.
Any help is greatly appreciated.
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Re: [Tutor] how to split/partition a string on keywords?
Thanks everyone. As I'm learning programming what I find most interesting
is that there's always more than one way to solve a problem.
I implemented eryksun's suggestion and used the replace() method.
But, playing around with it, what I discovered is that it won't store the
change.
For example, when the input text is, "Ham and cheese or chicken and
waffles":
#!/usr/bin/python
text = raw_input("Enter text: ")
print text.replace("and", "\nand").replace("or", "\nor")
I get:
Ham
and cheese
or chicken
and waffles.
But if I run the following:
#!/usr/bin/python
text = raw_input("Enter text: ")
text.replace("and", "\nand")
text.replace("or", "\nor")
print text
I get the text as it was entered.
Is there a way to replace text in a string without splitting or
partitioning?
The bigger picture for this little project is a "poetry machine", in which
a user enters some prose and the program chops it up into modern poetry.
So, this is a long shot naive noob question, but is there any way to count
syllables in words in a string? Or at least approximate this procedure?
On Thu, Aug 23, 2012 at 3:08 PM, wrote:
> This question seemed a good excercise so I banged out a little script
> (which worked) but latter I saw posts showing code that by using string
> method 'partition' provided a more elegant solution.
> I was previously unaware of this method. My "bible" has been David M.
> Beazley's Python Essential Reference (3rdEd) in which this method is not
> mentioned (that I can see.)
> Should I switch "bibles?"
> (I often find myself wanting to hack in "off line environments" so
> something as old fashion as a book would be nice:-)
>
> Here's my script for what it's worth:
>
> #!/usr/bin/env python
>
> import sys
>
> usage = """test0 separator
> Requires one parameter, the text to be used to separate the input which
> will be requested by the program."""
>
> if len(sys.argv) != 2:
> print usage
> separator = sys.argv[1]
>
> def separate(string, separator):
> ret = []
> i = string.find(separator)
> l = len(separator)
> while i > 0:
> ret.append(string[:i])
> ret.append(separator)
> string = string[i+l:]
> i = string.find(separator)
> ret.append(string)
> return ret
>
> def repart(string, separator):
> """Does the same as separator but using string method 'partition'"""
> parts = string.partition(separator)
> if parts[0] == string:
> return (parts[0], )
> else:
> return parts[:-1] + repart(parts[-1], separator)
>
> input_str = raw_input("Enter text to split on '%s': "%(separator, ))
>
> separated_array = separate(input_str, separator)
> for s in separated_array:
> print s
> parted_array = repart(input_str, separator)
> for s in parted_array:
> print s
>
>
>
>
> > Hi all,
> > I'm new to programming and Python.
> > I want to write a script that takes a string input and breaks the string
> > at
> > keywords then outputs the pieces on separate lines.
> > I'm not sure how to break the string, though.
> > I looked through the docs and found split() and partition(), which come
> > close.
> > But split() doesn't retain the separator and partition() retains the
> white
> > space and returns a 3-tuple which I'll have to figure out how to rejoin
> > nor
> > does it partition on subsequent instances of the separator.
> >
> > Here's the script in its basic form:
> >
> > #!/usr/bin/python
> >
> > text = raw_input("Enter text: ")
> > print "You entered ", text
> >
> > objects = text.partition(' and')
> > print objects
> >
> > for object in objects:# Second Example
> >
> >print object
> >
> > For example, if I run this with the input:
> > "Ham and cheese omelette with hasbrowns and coffee."
> > I get:
> > Ham
> > and
> > cheese omelette with hashbrowns and coffee.
> >
> > Any help is greatly appreciated.
> > ___
> > Tutor maillist - Tutor@python.org
> > To unsubscribe or change subscription options:
> > http://mail.python.org/mailman/listinfo/tutor
> >
>
>
>
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[Tutor] python as poetry
I don't know if it's appropriate to post things like this on the list, but I've learned a lot from this group and thought I'd share something I think you all will enjoy: http://www.thehelloworldprogram.com/videos/poetry-corner-red-wheelbarrow/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] I need a good resource for python Django
> Hi, > > Can anyone suggest me a good resource for python Django. I've gone through > the official website of Django but it is of limited use to me. Any help on > this would be highly appreciated. I recommend Mike Hibbert's YouTube series on Django. http://www.youtube.com/watch?v=oT1A1KKf0SI&feature=c4-overview-vl&list=PLxxA5z-8B2xk4szCgFmgonNcCboyNneMD It's the most comprehensive and easy to follow tutorial I've found. Otherwise go to the Google django-users group and search. Someone asks this question everyday. -- http://jarednielsen.com http://thehelloworldprogram.com http://dototot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] how to only loop over first 'x' items of a list; writing a Twitter bot with tweepy
Hi all, Noob. For a beginner project I'm hacking together a Twitter bot with tweepy. I've got one more or less functional, but I'm running into a problem when making a list of followers by calling the Twitter api. I'm getting a 'Rate limit exceeded' error, which, evidently is due to changes in the Twitter api not allowing one to make more than a certain number of calls. I think 150 at a time. I have more than 150 followers in the account. My code is: for follower in tweepy.Cursor(api.followers).items(): follower_ids.append(follower.id) My question is: how do I grab the first 'x' items in tweepy.Cursor(api.followers)items(), say 15 or 20, without looping through the entire list of items, which then gives me the error. Thanks! -- http://thehelloworldprogram.com http://dototot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] how to iterate through a dictionary and assign list values?
I want to create a dictionary, assign it keys, then iterate through a for
loop and assign the dictionary values from a list. I'm trying this, but
it's not working:
dictionary = {"one", "two", "three"}
list = [1,2,3]
for key in dictionary:
for value in list:
dictionary[key] = value
I get this error:
TypeError: 'set' object does not support item assignment
What am I doing wrong? Any help is greatly appreciated.
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[Tutor] question about strip() and list comprehension
Hello,
Could someone explain why and how this list comprehension with strip()
works?
f = open('file.txt')
t = [t for t in f.readlines() if t.strip()]
f.close()
print "".join(t)
I had a very long file of strings filled with blank lines I wanted to
remove. I did some Googling and found the above code snippet, but no clear
explanation as to why it works. I'm particularly confused by how "if
t.strip()" is removing the blank lines. I also don't fully understand the
'print "".join(t)'.
The above didn't remove the leading white space on several lines, so I made
the following addition:
f = open('file.txt')
t = [t for t in f.readlines() if t.strip()]
f.close()
s = [x.lstrip() for x in t]
print "".join(s)
List comprehensions are still magic to me. How would I go about
incorporating lstrip() in the first list comprehension?
Many thanks,
J.
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Re: [Tutor] question about strip() and list comprehension
Thank Danny,
That's much more clear.
But I still don't understand what's happening with:
if line.strip()
Is that stripping the line of white space at the same time that it is
testing it?
On Tue, Apr 8, 2014 at 3:44 PM, Danny Yoo wrote:
> > Could someone explain why and how this list comprehension with strip()
> > works?
> >
> > f = open('file.txt')
> > t = [t for t in f.readlines() if t.strip()]
> > f.close()
> > print "".join(t)
>
>
> Hi Jared,
>
>
> Let me rewrite this without the list comprehension, while preserving
> behavior.
>
> ##
> inputFile = open('file.txt')
> lines = []
> for line in inputFile.readlines():
> if line.strip():
> lines.append(line)
> inputFile.close()
> print "".join(lines)
> ##
>
> I am changing the names of the variables from the original code
> because I find it very difficult to distinguish 't' from 'f'
> sometimes, and because those names are very tied in my mind to
> something else entirely ("true" and "false").
>
>
> Does the above code make more sense to you than the version using the
> list comprehension syntax, or is there something there that is still
> confusing?
>
>
> Good luck to you.
>
--
http://jarednielsen.com
http://thehelloworldprogram.com
http://dototot.com
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Re: [Tutor] question about strip() and list comprehension
Thanks Danny! That was an awesome explanation. On Tue, Apr 8, 2014 at 7:05 PM, Danny Yoo wrote: > >> if line.strip() >> >> Is that stripping the line of white space at the same time that it is >> testing it? >> >> > > Two features about Python: > > 1. Strings are immutable, so the above is computing what a > whitespace-stripped line would look like. So that means that > 'line.strip()' is doing just a computation: it's not mutating the original > line, but computing a new string that has its leading and trailing > whitespace stripped away. > > > 2. Empty strings are treated as false values. I'm not happy with how > loose Python treats truth, and would rather prefer: > > if line.strip() != "": ... > > so that the thing being tested is explicitly either True or False. I like > my truth to be black and white, but I suppose I'll have to grimace and bear > the fuzziness. :P > > > Together, we see those two features allow us to look at the test in the > Python code: > >if line.strip(): ... > > and rephrase it in English as: > >"If the line consists of at least one non-whitespace character: ..." > -- http://jarednielsen.com http://thehelloworldprogram.com http://dototot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] difference between expressions and statements
Hi Pythons,
Could someone explain the difference between expressions and statements?
I know that expressions are statements that produce a value.
I'm unclear on functions and especially strings.
Are any of the following expressions?
print(42)
print("spam")
spam = 42
print(spam)
Is the first example producing a value or simply displaying an integer?
Does a string count as a value?
Is a variable assignment considered a value?
If I print a variable is that considered production of a value?
Thanks!
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Re: [Tutor] difference between expressions and statements
Thanks for the thorough answer, Bob. I now understand the difference.
On Apr 10, 2014 2:11 PM, "bob gailer" wrote:
> Caveat: I began this before there were any other responses. So this may be
> overkill - but I ike to be thorough.
>
> On 4/9/2014 12:49 PM, Jared Nielsen wrote:
>
>> Hi Pythons,
>> Could someone explain the difference between expressions and statements?
>>
>>> I know that expressions are statements that produce a value.
>>>
>> No. Expressions are not statements. These are mutually exclusive.
>> Expressions do produce values.
>>
> An attempt at a thorough answer:
>
> In the language reference glossary under "expression" you will find:
>
> "A piece of syntax which can be evaluated to some value. In other words,
> an expression is an accumulation of expression elements like literals,
> names, attribute access, operators or function calls which all return a
> value There are also statements which cannot be used as expressions,
> such as if. Assignments are also statements, not expressions."
>
> Tthe above is a quote; I don't like some of the grammar.
>
> In your examples print is a function. So all calls to print are
> expressions.
>
> In the language reference you will also find:
>
> 7. Simple statements
> 7.1. Expression statements
> 7.2. Assignment statements
> 7.3. The assert statement
> 7.4. The pass statement
> 7.5. The del statement
> 7.6. The return statement
> 7.7. The yield statement
> 7.8. The raise statement
> 7.9. The break statement
> 7.10. The continue statement
> 7.11. The import statement
> 7.12. The global statement
> 7.13. The nonlocal statement
> 8. Compound statements
> 8.1. The if statement
> 8.2. The while statement
> 8.3. The for statement
> 8.4. The try statement
> 8.5. The with statement
> 8.6. Function definitions
> 8.7. Class definitions
>
> With the exception of
> - 7.1. Expression statements
> - all of the above are either start with a keyword except 7.2 assignment
> which is indicated by an equal sign (=) .
> - all of the above cause something to happen (except pass), and do not
> return a value.
>
> 7.1. Expression statement is either one expression or several separated by
> commas.
> Used interactively to display value(s).
> Used anywhere to make a function call.
>
>> I'm unclear on functions and especially strings.
>> Are any of the following expressions?
>>
>> print(42)
>> print("spam")
>> spam = 42
>> print(spam)
>>
>> Is the first example producing a value or simply displaying an integer?
>>
> All function calls return a value. In the case of print the return value
> is always None.
> spam = 42 is a statement. (indicated by the = sign. 42 is a value.
>
>> Does a string count as a value?
>> Yes - however I suspect you are limiting "string" to something within
>> quotes. Those are "string literals".
>> Is a variable assignment considered a value?
>>
> No
>
>> If I print a variable is that considered production of a value?
>>
> See above comment on print.
>
> Long but comprehensive answer. Feel free to ask questions.
>
> Note there are various subtleties here -some keywords may be used to
> start a statement or in an expression - e.g. if, else, for yield.
>
> This also raises the fact that else (inter ala) is neither an expression
> or a statement; rather it is part of a compound statement. Nothing is
> simple.
>
> Oh there is more but I may never hit send
>
>
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