Regular Expressions 101

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"
(?i)hello
"
g
(?i)
match the remainder of the pattern with the following effective flags: gi
i modifier: insensitive. Case insensitive match (ignores case of [a-zA-Z])
hello
matches the characters hello literally (case insensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.

Regular Expression
No Match

r"
"
g

Test String