Lua Programming/stringlib
FacilitiesEdit
string.byteEdit
string.charEdit
string.dumpEdit
string.findEdit
string.formatEdit
string.gmatchEdit
string.gsubEdit
string.lenEdit
UsageEdit
string.len(STRING)
DescriptionEdit
The string.len function returns the length of the string argument.
print (string.len("Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch")) -- Returns 58
Embedded nul charactersEdit
Embedded nul characters do not terminate the string and are also counted by this function.
print (string.len("ab\000cd\000")) -- Returns 6
The length operator can also be used to determine the length of a stringEdit
The lua programming language provides a length operator, which can also be used to determine the length of a string:
print (#"Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch") -- Returns 58
string.lowerEdit
string.matchEdit
string.repEdit
string.reverseEdit
UsageEdit
string.reverse(STRING)
DescriptionEdit
The string.reverse function can be used for reversing string and returns the string with its character order reversed:
print (string.reverse("anut fo raj a rof tun A")) -- A nut for a jar of tuna
string.subEdit
UsageEdit
string.sub(STRING, STARTPOS [, ENDPOS])
DescriptionEdit
The string.sub function returns a substring of the string argument from a start position, and an optional end position.
print (string.sub("cheese salad sandwich",8)) -- position 8 onwards gives us "salad sandwich"
print (string.sub("cheese salad sandwich",1,12) -- positions 1 to 12 gives us "cheese salad"
The start position cannot be omitted, but the end position may be omittedEdit
Note that the start position is not optional, so for substrings starting at the first position, a parameter of one must be provided:
-- This does not work
print (string.sub("cheese salad sandwich",,12) -- we cannot omit the start position
-- To fix this, we must provide a substring position
print (string.sub("cheese salad sandwich",1,12) -- we want a substring from position 1
The end position can be omitted or negativeEdit
Without an end position, the substring continues to the end of the string:
print (string.sub("cheese salad sandwich",8)) -- position 8 onwards gives us "salad sandwich"
String positions may be negativeEdit
The end position can be negative. A negative value indicates the number of characters from the end, with -1 meaning the last character, -2 meaning the last but one character, etc:
print (string.sub("cheese salad sandwich",-8)) -- start 8 characters from the end gives "sandwich"
print (string.sub("cheese salad sandwich",1,-9)) -- drop " sandwich" to give "cheese salad"