searching a string substring using regex in python - regex

Question

hello i'm trying to search a string for its substrings and return "yes" if found.
for exp : i have string Deracu876, substrings are {D,d,e,E,r,R,A,a,c,C,u,U,8,7,6} so here is the result :
deracu876 :yes
Deracu8762:no
Dderacu876 : yes
sNdAp725:no
here is the code i wrote using regex but not working
import re
def match(text,pattern):
# regex
# searching pattern
if re.search(pattern,text,re.IGNORECASE):
return('Yes')
else:
return('No')
text=input()
pattern=""
for w in text :
pattern=pattern+'|'+w
print(match("Deracu8762",pattern))

Answer 1

Your for loop is putting a | at the beginning of the pattern, e.g. if text is abc, the pattern is |a|b|c. This will match an empty string, which is a substring of every string.
You can simply wrap [] around the characters, e.g. [deracu876]'. This matches any of those characters.
You also need to make another pattern that rejects characters that aren't in text. You can do this by putting the characters in [^], e.g. [^deracu876].
def match(text, substring):
if re.search('[' + substring + ']', text, re.IGNORECASE) and not re.search('[^' + substring '], text, re.IGNORECASE):
return "True"
else:
return "False"
text = input()
print(match("Deracu8762",text))