import re
 
 
corpus = []
 
x = "12/1/2017"
if re.search(r'\d{2}/\d{2}/\d{4}',x):  ### for mm/dd/yyyy
    y= re.findall(r'\d{2}/\d{2}/\d{4}',x)
    corpus.append(y)
elif re.search(r'\d{2}/\d/\d{4}',x): ### for mm/d/yyyy
    y= re.findall(r'\d{2}/\d/\d{4}',x)
    corpus.append(y)
elif re.search(r'\d/\d{2}/\d{4}',x): ### for m/dd/yyyy
    y= re.findall(r'\d/\d{2}/\d{4}',x)
    corpus.append(y)
elif re.search(r'\d/\d/\d{4}',x): ### for m/d/yyyy
    y= re.findall(r'\d/\d/\d{4}',x)
    corpus.append(y)
else:                     ### empty cells or says nan
    y=["00/00/0000"]
    corpus.append(y)
 
print(corpus)

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