Left$
left$ extracts a sub-string of a string starting from the beginning (the left side).
Syntax
left$(EXPR_STRING,EXPR_LEN)
EXPR_STRINGis an expression that gives the string from which the substring is extracted.EXPR_LENgives the number of characters to be extracted.
Examples
# Extraction of the first 5 letter of the latin alphabet
ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
FIRST_FIVE=left$(ALPHABET, 5) : # Returns "ABCDE"
# Computes the length of a string
# It would be preferable to use len!!!
STRING_LEN = 0
While left$(MY_STRING,STRING_LEN) <> MY_STRING : STRING_LEN+=1 : Wend
# Truncates a string to a maximum length of 32
# the string remains unchanged if its length was smaller than 32
MY_STRING=left$(MY_STRING,32)
# Truncates a clob to a maximum length of 800
# the clob remains unchanged if its length was smaller than 800
MY_CLOB=left$(MY_CLOB,800)
Description
The function left$ extracts the first EXPR_LEN characters of a string or a CLOB. According to EXPR_LEN, the type of the result is Char or Clbfile.
Comments
- If
EXPR_LENis equal to 0, the empty string""is returned. - If
EXPR_LENis greater than the length of the string, the string is returned.
Associated errors
| Error code | Description |
|---|---|
| 10 | The first argument is not a string, or the second argument is not numeric. |
| 50 | The second argument is negative. |