What is the match_all() method in Euphoria?
Overview
The match_all() method in Euphoria searches a sequence called the haystack to find all of another sequence called the needle. The start position of this search can also be indicated.
On successful matching of all items of needle in the haystack, a value that has the index of the first matched character in the sequence is returned. If all of the needle is not matched in the haystack, we get back an empty sequence.
Syntax
match_all(needle,haystack, start)
Parameters
-
needle: This is a sequence that contains values that will be checked/searched in thehaystack. -
haystack: This is the sequence that will be searched through for a match. -
start: This is the integer value which indicates where the search for a match is to start.
Return value
The match_all function returns a sequence.
This sequence contains an index of the first matched character in the needle. It means it returns the index of the point at which the match starts.
Note: If we provide the
needleargument as an empty sequence the parser will raise an error and exit the program.
Code
Let's look at the code below:
--import the search moduleinclude std/search.e--declare some variablessequence needle1, needle2, needle3, needle4sequence result1, result2, result3, result4--assign values to declared variablesneedle1 = "first needle"needle2 = "these are"needle3 = "is the"needle4 = {"sure","the","second","matches"}--call the function match_all function--checks for a match starting at index `13`.result1 = match_all(needle1,"This is the first needle",13)--no match is foundresult2 = match_all(needle2,"This is the first")--a match 'is the' is found at index 6result3 = match_all(needle3,"This is the first")--the whole haystack matches the needle; needle4result4 = match_all(needle4,{"sure","the","second","matches"})--display our output so farprint(1,result1)puts(1,"\n")print(1,result2)puts(1,"\n")print(1,result3)puts(1,"\n")print(1,result4)
Explanation
-
Line 2: We import the
search.einbuilt module which enables us to use thematch_all()method. -
Lines 5 and 6: We declare a group of variables for the
needleand another for holding theresultsas a sequence. -
Lines 9 to 12: We assign values to the declared group of
needlevariables. -
Lines 16, 18, 21, and 24: We call the
match_all()method and use it in different ways to explore the possible outcomes. The output is also assigned to the group ofresultvariables declared previously. -
Lines 28 to 34: The output of the
match_all()method is printed to the screen.
