Home- for ch in string.utf8fwd(str [, i [, j]]) ...
- for ch in string.utf8rev(str [, i [, j]]) ...
SYNOPSIS
DESCRIPTION
These functions set allow iterating over a string with UTF8 encoding in forward and reverse direction.
Without further arguments, iterates over the full str contents.
Parameters select a substring of str that starts at i and continues until j; i and j can be negative. If j is absent, then it is assumed to be equal to -1 (which is the same as the string length). In particular, the parameters (str,1,j) iterate over prefix of str with length j, and the parameters (str, -i) iterate over the last i codepoints of str.
RETURN VALUE
Each iteration provides a numeric character code until the loop ends.
NOTES
Using an iterator walks the string in O(n) forward and O(2n) in reverse, while doing a naive loop using
string.utf8at() takes O(n²).
EXAMPLE
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s = "Sm\xC3\xB8rebr\xC3\xB8d"
print(s)
for ch in string.utf8fwd(s) do
print(ch)
end
Smørebrød
83
109
248
114
101
98
114
248
100