这个列表理解我哪里出错了？

Question

I want to extract the 4 digit year (2000) from a string or return None or NaN if its not present.

w = 'A70-11370; reprint; rolled; 2000; 26.5 x 38.5'

I tried this but I get a syntax error.

[int(i) for i in w.split(';') if i.isnumeric() else np.nan]

Answer 1

I'd strip the whitespace and reposition the validation check:

In[0]: [int(i.strip()) if str(i.strip()).isnumeric() else np.NaN for i in w.split(';')]
Out[0]: [nan, nan, nan, 2000, nan]

Answer 2

This must surely work

x=w.split('; ')

if x[3] == ' ':
    print ("null")
else:
    print (x[3])