SEG$

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seg$ is used to extract a sub-string located between two positions in a character string.

 

Syntax

   seg$( string, start, end )

 

Parameters

Element

Description

Restrictions

string

Alphanumeric expression

None.

start

Numerical integer expression for the position extraction begins.

start >= 0

end

Numerical integer expression for the position where extraction stops.

end > = 0

 

Examples

   # Extraction of letters of the alphabet between the 3rd and 8th letters;
   # this programme displays "CDEFGH"
    ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    Infbox seg$(ALPHABET, 3, 8)

 

Description and comments

The function seg$(string, start, end) extracts the characters of the string from the start position up to the end position inclusive. It therefore extracts at the most start-end+1.

The result is a Char type.

Comment

If start is greater than the length of the chain, or if start is greater than end, seg$(string, start, end) returns the empty string "". If the length of string is insufficient, that is, if fin > len(string), the number of characters extracted will be fewer than fin-début+1. An error is never generated from one of these two conditions.

 

Associated errors

Error

Description

ERMODE (10)

The arguments are not of the corresponding type.

ERDOM (50)

start < 0 or end < 0.

 

Associated key words

MID$ - LEN - RIGHT$ - LEFT$


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