Regular Expressions 101

^start of line

Negated Character Class[^ #;\[]{77}

{77}matches exactly 77 characters outside the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

#the literal # (35₁₀ / 43₈ / 23₁₆)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^[^ #;\[]{77}$

Test String
New

lets_make_a_snake<-function(n)`for`(i,1:n,cat(i*n+1-`if`(i%%2,n:1,1:n),"\n"))
invisible(sapply(1:(n=scan()),function(i)cat(i*n+1-`if`(i%%2,n:1,1:n),"\n")))

Regular Expression

Test StringNew

Test String
New