string index string charIndex

Returns the charIndex 'th character of the string argument. A charIndex of 0 corresponds to the first character of the string. charIndex may be specified as follows:

integer — The char specified at this integral index.

end — The last char of the string.

end-integer — The last char of the string minus the specified integer offset (e.g. end-1 would refer to the "c" in "abcd").

If charIndex is less than 0 or greater than or equal to the length of the string then an empty string is returned.

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AMG: TIP #176 [1] adds two more more indexing modes: integer-integer and integer+integer. These are certainly convenient. However, due to the fundamental need for concatenation and reparsing in any practical application, they are also slightly slower than just using [expr] to do the math. (Remember to always brace your expr-essions!)

There's also another mode which may be occasionally useful: end+integer. This comes in handy when the integer in question is already negative.

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Returns for index an integer, the charIndex'th character in string. If index is end, the last character in string, and if index is end-integer, the last character minus the specified offset. (From the Tcl/Tk Reference Guide)

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For example,

   string index abcde 3

returns "d" . Notice that the index is zero based - the first character is index 0.

   string index abcde 10

returns "" . There is no 10th character. No error is returned here.

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See also edit

• string
• string range

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