# What meaning is "if k in [0, len(n_trials) - 1] else None"?

Robert rxjwg98 at gmail.com
Sat Dec 3 18:08:52 EST 2016

```Hi,

I am trying to understand the meaning of the below code snippet. Though I have
a Python IDLE at computer, I can't get a way to know below line:

if k in [0, len(n_trials) - 1] else None

I feel it is strange for what returns when the 'if' condition is true?
The second part 'None' is clear to me though.

Could you explain it to me?

thanks,

%matplotlib inline
from IPython.core.pylabtools import figsize
import numpy as np
from matplotlib import pyplot as plt
figsize(11, 9)

import scipy.stats as stats

dist = stats.beta
n_trials = [0, 1, 2, 3, 4, 5, 8, 15, 50, 500]
data = stats.bernoulli.rvs(0.5, size=n_trials[-1])
x = np.linspace(0, 1, 100)

# For the already prepared, I'm using Binomial's conj. prior.
for k, N in enumerate(n_trials):
sx = plt.subplot(len(n_trials) / 2, 2, k + 1)
if k in [0, len(n_trials) - 1] else None
plt.setp(sx.get_yticklabels(), visible=False)
plt.fill_between(x, 0, y, color="#348ABD", alpha=0.4)
plt.vlines(0.5, 0, 4, color="k", linestyles="--", lw=1)

leg = plt.legend()
leg.get_frame().set_alpha(0.4)
plt.autoscale(tight=True
```