I have built a code for a codewars problem. I think it is correct but it shows me an error I don't understand.
Can you tell me what am I doing wrong?
import math
def waterbombs(fire, w):
s=""
countx=0
for i in fire:
if i=="x":
countx+=1
elif i=="Y":
countx=0
return sum(math.ceil(countx/w))
waterbombs("xxYxx", 3)
This is the error:
Traceback (most recent call last):
File "D:\Curso Python Pildorasinformaticas\Ejercicios Codewars\Aerial Firefighting.py", line 16, in <module>
waterbombs("xxYxx", 3)
File "D:\Curso Python Pildorasinformaticas\Ejercicios Codewars\Aerial Firefighting.py", line 13, in waterbombs
return sum(math.ceil(countx/w))
TypeError: 'int' object is not iterable
[Finished in 0.2s]
Why are you doing sum(math.ceil(countx/w)) ?
What is the objective of the sum method here, since there is only value returned by math.ceil ?
The sum would throw that error if you pass a single value to it. You're supposed to pass a list of values of the sum method.
For eg: sum(5) would give you the same error you see above, but sum([5]) would return you 5.
Related
Here is the code for my question. I was trying to translate a pseudocode into python. The function, ExCamel, forms a return string, OutString, from a given string,InString,by:
1:Separating the original words(a word is assumed to start with a capital letter)
2:Converting all characters to lower case.
InString=str(input("Enter a statement: "))
def ExCamel(InString):
NextChar=chr()
OutString=str()
n=int()
OutString=""
return OutString
for n in range(1,len(ExCamel(Instring))):
NextChar=InString[n:n+1]
if NextChar==upper(NextChar):
if n>1:
OutString=OutString+""
NextChar=lower(NextChar)
OutString=OutString+NextChar
But it gives an output of:
Traceback (most recent call last):
File "C:/Users/user/PycharmProjects/George/TrynaCreate.py", line 7, in <module>
for n in range(1,len(ExCamel(Instring))):
NameError: name 'Instring' is not defined
This just seems like a silly mistake which happens with most of us:
you have defined
InString
but you are using In's'tring
Hope that helps :)
I have this for-loop:
for i in range(1000000000, 1000000030):
foo(i)
When I execute it this error is given:
Traceback (most recent call last):
File "/CENSORED/Activity.py", line 11, in <module>
for i in range(1000000000, 10000000030):
OverflowError: range() result has too many items.
As far as I know, this range-object should have exactly 30 elements...
Where is the problem?
Edit:
I have removed the extra zero, now I get this:
Traceback (most recent call last):
File "/CENSORED/Activity.py", line 12, in <module>
factorizeInefficient(i)
MemoryError
Edit 2:
def factorizeInefficient(n):
teiler = list()
for i in range(n):
if i != 0:
if (n%i)==0:
teiler.append(i)
print teiler
Just found the solution myself: There is a range(n) object in this as well and this causes the memory Error...
An extra question: How did you guys know this was python 2? (Btw you were right...)
Copy/pasting the range() part of your code:
>>> len(range(1000000000, 10000000030))
9000000030
So there are actually about 9 billion elements in the range. Your first argument is presumably missing a zero, or second argument has a zero too many ;-)
count your zeros once again ;) I'd say it's one too much.
The code gives an error because the value of "var" is very close to zero, less than 1e-80. I tried to fix this error using "Import decimal *", but it didn't really work. Is there a way to tell Python to round a number to zero when float number is very close to zero, i.e. < 1e-50? Or any other way to fix this issue?
Thank you
CODE:
import math
H=6.6260755e-27
K=1.3807e-16
C=2.9979E+10
T=100.0
x=3.07175e-05
cst=2.0*H*H*(C**3.0)/(K*T*T*(x**6.0))
a=H*C/(K*T*x)
var=cst*math.exp(a)/((math.exp(a)-1.0)**2.0)
print var
OUTPUT:
Traceback (most recent call last):
File "test.py", line 11, in <module>
var=cst*math.exp(a)/((math.exp(a)-1.0)**2.0)
OverflowError: (34, 'Numerical result out of range')
To Kevin:
The code was edited with following lines:
from decimal import *
getcontext().prec = 7
cst=Decimal(2.0*H*H*(C**3.0)/(K*T*T*(x**6.0)))
a=Decimal(H*C/(K*T*x))
The problem is that (math.exp(a)-1.0)**2.0 is too large to hold as an intermediate result.
>>> (math.exp(a) - 1.0)**2.0
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OverflowError: (34, 'Result too large')
However, for the value of a you are using,
>>> math.exp(a)/(math.exp(a)-1.0) == 1.0
True
so you can essentially cancel that part of the fraction, leaving
var = cst/(math.exp(a)-1.0)
which evaluates nicely to
>>> cst/(math.exp(a)-1.0)
7.932672271698049e-186
If you aren't comfortable rewriting the formula to that extent, use the associativity of the operations to avoid the large intermediate value. The resulting product is the same.
>>> cst/(math.exp(a)-1.0)*math.exp(a)/(math.exp(a)-1.0)
7.932672271698049e-186
I solved this issue but that will work only for this particular problem, not in general. The main issue is the nature of this function:
math.exp(a)/(math.exp(a)-1.0)**2.0
which decays very rapidly.
Problem can be easily solved restricting the value of "a" (which won't make any significant change in calculation). i.e.
if a>200:
var=0.0
else:
var=cst*math.exp(a)/((math.exp(a)-1.0)**2.0)
I am trying to take the inverse Fourier transform of a list, and for some reason I keep getting the following error
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "simulating_coherent_data.py", line 238, in <module>
exec('ift%s = np.fft.ifft(nd.array(FTxSQRT_PS%s))'(x,x))
TypeError: 'str' object is not callable
And I can't figure out where I have a string. The part of my code it relates to is as follows
def FTxSQRT_PS(FT,PS):
# Import: The Fourier Transform and the Power Spectrum, both as lists
# Export: The result of FTxsqrt(PS), as a list
# Function:
# Takes each element in the FT and PS and finds FTxsqrt(PS) for each
# appends each results to a list called signal
signal = []
print type(PS)
for x in range(len(FT)):
indiv_signal = np.abs(FT[x])*math.sqrt(PS[x])
signal.append(indiv_signal)
return signal
for x in range(1,number_timesteps+1):
exec('FTxSQRT_PS%s = FTxSQRT_PS(fshift%s,power_spectrum%s)'%(x,x,x))
exec('ift%s = np.fft.ifft(FTxSQRT_PS%s)'(x,x))
Where FTxSQRT_PS%s are all lists. fshift%s is a np.array and power_spectrum%s is a list. I've also tried setting the type for FTxSQRT_PS%s as a np.array but that did not help.
I have very similar code a few lines up that works fine;
for x in range(1,number_timesteps+1):
exec('fft%s = np.fft.fft(source%s)'%(x,x))
where source%s are all type np.array
The only thing I can think of is that maybe np.fft.ifft is not how I should be taking the inverse Fourier transform for Python 2.7.6 but I also cannot find an alternative.
Let me know if you'd like to see the whole code, there is about 240 lines up to where I'm having trouble, though a lot of that is commenting.
Thanks for any help,
Teresa
You are missing a %
exec('ift%s = np.fft.ifft(FTxSQRT_PS%s)'(x,x))
Should be:
exec('ift%s = np.fft.ifft(FTxSQRT_PS%s)'%(x,x))
We just learned for loops in class for about five minutes and we were already given a lab. I am trying but still not getting what I need to get. What I am trying to do is take a list of integers, and then only take the odd integers and add them up and then return them so if the list of integers was [3,2,4,7,2,4,1,3,2] the returned value would be 14
def f(ls):
ct=0
for x in (f(ls)):
if x%2==1:
ct+=x
return(ct)
print(f[2,5,4,6,7,8,2])
the error code reads
Traceback (most recent call last):
File "C:/Users/Ian/Documents/Python/Labs/lab8.py", line 10, in <module>
print(f[2,5,4,6,7,8,2])
TypeError: 'function' object is not subscriptable
Just a couple of minor mistakes:
def f(ls):
ct = 0
for x in ls:
# ^ Do not call the method, but just parse through the list
if x % 2 == 1:
ct += x
return(ct)
# ^ ^ parenthesis are not necessary
print(f([2,5,4,6,7,8,2]))
# ^ ^ Missing paranthesis
You're missing the parenthesis in the function call
print(f([2,5,4,6,7,8,2]))
rather than
print(f[2,5,4,6,7,8,2])