Re: program python
Il giorno giovedì 4 marzo 2021 alle 23:51:39 UTC+1 Igor Korot ha scritto:
> Hi,
> On Thu, Mar 4, 2021 at 4:42 PM alberto wrote:
> >
> > Il giorno giovedì 4 marzo 2021 alle 22:04:57 UTC+1 Paul Bryan ha scritto:
> > > I don't see a Python program in that link.
> > >
> > > Are you asking how to extract data from a CSV?
> > > A good start will be to look into the csv.reader function and
> > > csv.DictReader class.
> > >
> > > Paul
> > > On Thu, 2021-03-04 at 12:36 -0800, alberto wrote:
> > > > Hi I'm tring to write a program with python to evaluate data of csv
> > > > data
> > > > In particular I would extract this information
> > > >
> > > > View data on the presence of men and women in Affori over time.
> > > >
> > > > * Carry out an analysis relating to the last available year. Of the
> > > > 10 most populous neighborhoods show:
> > > > * the proportion of births out of the total
> > > > * the proportion of 80+ to the total
> > > > * The ratio of minors / number of kindergartens
> > > >
> > > > this is the file
> > > > https://drive.google.com/file/d/1zKflvSpB-oDAqYscLsEgUhSnqL1XPdql/view?usp=sharing
> > > >
> > > >
> > > > How could fix it?
> > > >
> > > > regards
> >
> > Hi,
> > with this code
> > import pandas as pd
> > df = pd.read_csv('data.csv',usecols=['Uomini','Donne'])
> >
> > print(df)
> > I extract two columns, but I would see 'Affori over time'
> And if you add this column to the list - what happens?
> Thank you.
>
> >
> > regards
> > --
> > https://mail.python.org/mailman/listinfo/python-list
Hi,
with pandas I obtain results!
Now I would calculate ratio beetween columns of my csv
import pandas as pd
pd.set_option('display.max_rows', 500)
df = pd.read_csv ('data_quartiere_2018.csv', usecols=
['Anno','Totale','Quartiere','Nati','80 e più soli','80 e
più','Minori','Scuola_infanzia (numero)'])
test = df.loc[df['Totale'] >= 31990,
print (test)
in particular I would calculate ratio beetween ('Nati'*100)/'Totale' when
['Totale'] >= 31990
How could fix it
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Re: Problem with printing statement when condition is false
On 3/4/2021 4:28 PM, Terry Reedy wrote:
Quentin privately sent me 12 lines (which should have been posted here
instead), which can be reduced to the following 4 that exhibit his bug.
if a == b:
print('correct')
if a != b:
print('incorrect')
The bug is a != b will never be true when a == b and will not be tested
when a != b. The fix is to use else.
if a == b:
print('correct')
else:
print('incorrect')
This should not be reduced to a conditional expression since different
code follows the print statements in the actual example.
Quentin wrote me privately that this, applied to his code, solved his
problem.
--
Terry Jan Reedy
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Re: Why assert is not a function?
On 03Mar2021 16:50, Grant Edwards wrote: >On 2021-03-03, Chris Angelico wrote: >> On Thu, Mar 4, 2021 at 1:40 AM Grant Edwards >> wrote: >> >>> I thought the entire point of asser being a keyword was so that if you >>> disable asserts then they go away completely: the arguments aren't >>> even evaluated. >> >> It depends on what the point of "removing the assertions" is, but >> yes, that will indeed still evaluate the arguments. IMO the cost of >> running assertions isn't that high compared to the value of keeping >> them (which is why I never run -O), and the performance argument is >> a weak one compared to the much stronger value of having the actual >> failing expression available in the exception report. > >Good point. I had forgotten about having the expression available in >the exception output. That's definitly valuable. Did we all see the recently announced ycecream PyPI module? Very cool! See: https://github.com/salabim/ycecream Cheers, Cameron Simpson -- https://mail.python.org/mailman/listinfo/python-list
trouble using pygame
So, I recently downloaded the pygame module, this code is from a youtube tutorial by the way, I am following along the tutorial, the error involves the pygame.init() and also says this: import pygame # Initialize Pygame pygame.init() #create the screen screen = pygame.display.set_mode((800, 600)) # Game Loop running = True while running: for event in pygame.event.get(): if event.type == pygame.quit(): running = False The error says "partially initialized module 'pygame' has no attribute 'init' (most likely due to a circular import) If someone could also explain what a circular import is and how to avoid them within the future that would be great Thanks :) Here is a link to the tutorial as well just in case someone wants to see it: https://www.youtube.com/watch?v=FfWpgLFMI7w -- https://mail.python.org/mailman/listinfo/python-list
Re: trouble using pygame
On 2021-03-06 02:54, Quentin Bock wrote: So, I recently downloaded the pygame module, this code is from a youtube tutorial by the way, I am following along the tutorial, the error involves the pygame.init() and also says this: import pygame # Initialize Pygame pygame.init() #create the screen screen = pygame.display.set_mode((800, 600)) # Game Loop running = True while running: for event in pygame.event.get(): if event.type == pygame.quit(): running = False The error says "partially initialized module 'pygame' has no attribute 'init' (most likely due to a circular import) If someone could also explain what a circular import is and how to avoid them within the future that would be great Thanks :) Here is a link to the tutorial as well just in case someone wants to see it: https://www.youtube.com/watch?v=FfWpgLFMI7w A circular import is when a module tries to import itself directly or indirectly. (A imports A; A imports B, which imports A; A imports B, which imports C, which imports A; you get the idea!) What did you call your script? Did you perhaps call it "pygame"? -- https://mail.python.org/mailman/listinfo/python-list
Question about generators
Hi all
This is purely academic, but I would like to understand the following -
>>>
>>> a = [('x', 'y')]
>>>
>>> s = []
>>> for b, c in a:
... s.append((b, c))
...
>>> s
[('x', 'y')]
This is what I expected.
>>>
>>> s = []
>>> s.append(((b, c) for b, c in a))
>>> s
[ at 0x019FC3F863C0>]
>>>
I expected the same as the first one.
I understand the concept that a generator does not return a value until
you call next() on it, but I have not grasped the essential difference
between the above two constructions.
TIA for any insights.
Frank Millman
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Re: Question about generators
>>> >>> s = [] >>> s.append(((b, c) for b, c in a)) >>> s [ at 0x019FC3F863C0>] >>> TIA for any insights. Replace "append" above with "extend" and observe the results. Then ponder the difference between append and extend. I suspect that the heart of your confusion actually has nothing to do with generators. -- Alan Bawden -- https://mail.python.org/mailman/listinfo/python-list
Re: Question about generators
On Sat, Mar 06, 2021 at 08:21:47AM +0200, Frank Millman wrote: > [...] > I understand the concept that a generator does not return a value until you > call next() on it, but I have not grasped the essential difference between > the above two constructions. > > TIA for any insights. > > Frank Millman In your first example, a certain element is appended to s each time in the loop. But in your second example, the generator first traverses all the elements, and then generates an iterable object, you are trying to append this object to s. Let's look at a simpler but more certain example: a = [1, 2, 3] s = [] for n in a: s.append(n) # Result: # len(s) == 3 # s == [1, 2, 3] a = [1, 2, 3] s = [] g = (n for n in a) s.append(g) # Result: # len(s) == 1 # list(s[0]) == [1, 2, 3] If you want to get the same result in the above two cases, just replace append with extend. list.extend() can accept an iterable object as input, and then append all the elements to the original list. -- OpenPGP fingerprint: 3C47 5977 4819 267E DD64 C7E4 6332 5675 A739 C74E signature.asc Description: PGP signature -- https://mail.python.org/mailman/listinfo/python-list
Re: Question about generators
On 2021-03-06 8:21 AM, Frank Millman wrote:
Hi all
This is purely academic, but I would like to understand the following -
>>>
>>> a = [('x', 'y')]
>>>
>>> s = []
>>> for b, c in a:
... s.append((b, c))
...
>>> s
[('x', 'y')]
This is what I expected.
>>>
>>> s = []
>>> s.append(((b, c) for b, c in a))
>>> s
[ at 0x019FC3F863C0>]
>>>
I expected the same as the first one.
I understand the concept that a generator does not return a value until
you call next() on it, but I have not grasped the essential difference
between the above two constructions.
Thanks, Alan and Ming.
I think I have got it now.
In my first example, a 'for' loop both creates an iterable object *and*
iterates over it.
In my second example, a generator expression creates an iterable object,
but does nothing with it until asked.
Changing 'append' to 'extend' has the effect of iterating over the
generator expression and appending the results.
Frank
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