I have what I believe to be an embarrassingly simple problem, but three hours of googling and checking stackoverflow have not helped.
Let's say I have a very simple piece of code:
def secret_formula(started):
jelly_beans = started*500
jars = jelly_beans/1000
crates = jars/100
return jelly_beans,jars,crates
start_point = 10000
print("We'd have {} beans, {} jars, and {} crates.".format(secret_formula(start_point)))
What happens is I get the "IndexError: tuple index out of range". So I just print the secret_formula function to see what it looks like, and it looks like this:
(5000000, 5000.0, 50.0)
Basically, it is treating the output as one 'thing' (I am still very new, sorry if my language is not correct). My question is, why does it treat it like this and how do I make it pass the three outputs (jelly_beans, jars, and crates) so that it formats the string properly?
Thanks!
The format function of the string take a variable number of argument. The secret_formula function is returning a tuple. You want to convert that to a list of arguments. This is done using the following syntax:
print("We'd have {} beans, {} jars, and {} crates.".format(*secret_formula(start_point)))
The important par is the * character. It tell that you want to convert the following iterable into a list of argument to pass to the function.
Related
I have created several Textarea widgets in Jupyter/Python in order to capture some string inputs.
In the highlighted in yellow that you can see below, the idea is that the user puts a list of numbers here (copied from Excel) and later I need to convert this text into a list or an array that contains these numbers (an iterable object). I have no idea how to do this. See:
When I print the type of this object that is called "plus" I get this:
print(type(plus))
<class 'ipywidgets.widgets.widget_string.Textarea'>
But, I am expecting to have something like this:
plus = [454, 555]
Can I bounce some ideas off you to get this?
Thanks a lot!!!
If you have an ipywidget in general, you can observe its change and get its value as following.
foo = widgets.Textarea()
# to get the value
foo.value
# to do something on value change
def bar(change):
print(change.new)
foo.observe(bar, names=['value'])
You will then have to format the string you get from the products value, but that shouldn't be too difficult.
Hope this helps
disclaimer: My title may not be accurate as far as what I would like to accomplish, but I can update if someone can correct my terminology
I have 2 functions, each with a separate purpose and usable on its own, but occasionally I would like to combine the two to perform both actions at once and return a single result, and to do this I would like to assign to a variable name
I know I can create a 3rd function that does basically what I want as it is really simple.. though it's become a bit of a challenge to myself to find a way of doing this
def str2bool(string):
return string.lower() in ("yes", "true", "t", "1")
def get_setting(string):
if string == 'cat':
return 'yes'
else:
return 'no'
VALID_BOOL = str2bool(get_setting)
print VALID_BOOL('cat')
So basically I would like to assign the combination of the 2 functions to a variable that I can call and pass in the string parameter to evaluate
In my real world code, get_setting() would retrieve a user setting and return the value, I would then like to test that value and return it as a boolean
Again I know I can just create a 3rd function that would get the value and do the quick test.. but this is more for learning to see if it can be done as I'm trying to do.. and so far my different variations of assigning and calling aren't working, is it even possible or would it turn too complex?
Using lambda is easy, but i don't know if it is exactly what you are looking for.
Example:
f = lambda astring : str2bool(get_setting(astring))
Outputs:
>>> f('cat')
True
Suppose I have a list like
list1 = ['A','B','1','2']
When i print it out I want the output as
AB12
And not
A B 1 2
So far I have tried
(a)print list1,
(b)for i in list1:
print i,
(c)for i in list1:
print "%s", %i
But none seem to work.
Can anyone suggest an alternate method
Thank you.
From your comments on #jftuga answer, I guess that the input you provided is not the one you're testing with. You have mixed contents in your list.
My answer will fix it for you:
lst = ['A','B',1,2]
print("".join([str(x) for x in lst]))
or
print("".join(map(str,lst)))
I'm not just joining the items since not all of them are strings, but I'm converting them to strings first, all in a nice generator comprehension which causes no memory overhead.
Works for lists with only strings in them too of course (there's no overhead to convert to str if already a str, even if I believed otherwise on my first version of that answer: Should I avoid converting to a string if a value is already a string?)
Try this:
a = "".join(list1)
print(a)
This will give you: AB12
Also, since list is a built-in Python class, do not use it as a variable name.
I'm newbie for python 2.7. I would like to create some function that knows which are variables in the given probability notation.
For example: Given a probability P(A,B,C|D,E,F) as string input. The function should return a list of events ['A','B','C'] and a list of sample spaces ['D','E','F']. If it is impossible to return two lists in the same time. Returning a list of two lists would be fine.
In summary:
Input:
somefunction('P(A,B,C|D,E,F)')
Expected output: [['A','B','C'],['D','E','F']]
Thank you in advance
A simple brute-force implementation. As #fjarri pointed out if you want to do anything more complex you might need a parser (like PyParser) or at least some regular expressions.
def somefunction(str):
str = str.strip()[str.index("(")+1:-1]
left, right = str.split("|")
return [left.split(","), right.split(",")]
Scala noob i'm afraid:
I have the following declared class variable which will the objects I read from the database:
val options = mutable.LinkedList[DivisionSelectOption]()
I then use JPA to get a List of all rows from a table:
val divisionOptions = em.createNamedQuery("SelectOption.all", classOf[SelectOption]) getResultList
/* Wrap java List in Scala List */
val wrappedOptions = JListWrapper.apply(divisionOptions)
/* Store the wrappedOptions in the class variable */
options += wrappedOptions
However, the last line has an error:
Type Expected: String, actual JListWrapper[SelectOption]
Can anyone help with what I am doing wrong? I'm just trying to populate the options object with the result of the DB call.
Thanks
What (probably) is happening is that a JlistWrapper[SelectOption] isn't a DivisionSelectOption, so the method += isn't applicable to it. That being the case, it is trying other stuff, and giving a final error on this:
options = options + wrappedOptions
That is a rewriting Scala can do to make things like x += 1 work for var x. The + method is present on all objects, but it takes a String as parameter -- that's so one can write stuff like options + ":" and have that work as in Java. But since wrappedOptions isn't a String, it complains.
Roundabout and confusing, I know, and even Odersky regrets his decision with regards to +. Let that be a lesson: if you thing of adding a method to Any, think really hard before doing it.