In Python and JavaScript, == compares strings too. In Raku, == compares numbers, and strings are compared with eq.
In Python and JavaScript, == works for anything. In Raku, == only compares numbers.
In Python
print("Riga" == "Riga")
print("10" == "10.0")True False
In JavaScript
console.log("Riga" == "Riga");
console.log("10" == "10.0");true false
In Raku
say "Riga" == "Riga";
Cannot convert string to number: base-10 number must begin with valid digits or '.'
== tries to turn both strings into numbers, and Riga is not a number.
When the strings do look like numbers, there is no error, and you get the opposite answer to Python’s:
say "10" == "10.0";
True
Ten is ten, however you write it. This case is the more dangerous one, because nothing tells you that the strings were never compared as strings.
Why
In Raku, the operator decides what kind of comparison you get. There is one set of operators for numbers and another one for strings:
| Question | Numbers | Strings |
|---|---|---|
| equal? | == |
eq |
| not equal? | != |
ne |
| less than? | < |
lt |
| greater than? | > |
gt |
Perl works the same way, so Perl programmers already have this habit:
print "10" == "10.0" ? "equal" : "different", "\n";
print "10" eq "10.0" ? "equal" : "different", "\n";equal different
Say it in Raku
say "Riga" eq "Riga"; say "10" eq "10.0"; say "Riga" ne "Rome"; say "Leiden" lt "Riga";
True False True True
lt compares in alphabetical order: Leiden comes before Riga.