Code:
a = 100
b = 10
p = prime_range(a)
for j in range(a/b):
fn[j] = [(i,val) for i,val in enumerate(p) if j * b < p[i] < (j+1) * b];
My code is able to partition prime numbers up to 100 in decades, but when I try to increase the prime range limit, or increase the partition then the code breaks. I am not sure why that happens? Could it be the if statement?
You didn't tell us about the line fn = [] before. That makes it a list of length 0, and fn[j] = ... tries to assign to other entries of that list. You could do any of these:
a = 100
b = 10
p = prime_range(a)
fn = []
for j in range(a/b):
fn.append([(i,val) for i,val in enumerate(p) if j * b < p[i] < (j+1) * b])
or
a = 100
b = 10
p = prime_range(a)
fn = [[(i,val) for i,val in enumerate(p) if j * b < p[i] < (j+1) * b] for j in range(a/b)]
or
a = 100
b = 10
p = prime_range(a)
fn = {}
for j in range(a/b):
fn[j] = [(i,val) for i,val in enumerate(p) if j * b < p[i] < (j+1) * b]
So I tried using the first two examples. Both do work when a=100, and b=10. However, when a=1000,and b=10. This is when I start having issues.
So when I try calculating the average, and median I get a division by zero error.
ZeroDivisionError Traceback (most recent call last)
<ipython-input-48-5a2c6df33de7> in <module>()
----> 1 fave = [sum(fn[i])/len(fn[i]) for i in range(len(fn))]
2 fmed = [median(fn[i]) for i in range(len(fn))]
<ipython-input-48-5a2c6df33de7> in <listcomp>(.0)
----> 1 fave = [sum(fn[i])/len(fn[i]) for i in range(len(fn))]
2 fmed = [median(fn[i]) for i in range(len(fn))]
ZeroDivisionError: division by zero
However when I check the average and median by checking an individual index of fn I get the correct number for said index.
sum(fn[0])/len(fn[0])
17/4
median(f[0])
4
Have you looked at fn? There are some empty lists in there, so len(fn[i]) will be zero.
No prime numbers between 200 and 210, for example, so you get an empty list for that entry.
Yea I wasn't thinking about there being empty list. So I guess I will have to do an if else statement to get around that.
Asked: 2022-04-27 17:44:00 +0100
Seen: 186 times
Last updated: Apr 30 '22
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How exactly it breaks? Please illustrate with an example.
Perhaps use
a//binstead ofa/bso that the argument torangeis an integer?Here is an error that I get. However, I am getting this error when a = 100, and b = 10.
IndexError Traceback (most recent call last)
<ipython-input-2-80f673aa11bb> in <module>()
----> 7 fn[j] = [(i,val) for i,val in enumerate(p) if jb < p[i] < (j+Integer(1))b];
IndexError: list assignment index out of range
I also tried the a//b, but that didn't work.