Evaluation of conditions is very important part programming. True is ture, false is false…
Or not? It might surprise you, but not all languages evaluate numbers, empty strings or empty arrays in the same way.
Let’s examine several technologies. Python, Ruby, PowerShell, NodeJS and PHP.
Here is small code written in Python:
def test(value):
if value:
print "True"
else:
print "False"
test(0)
test(1)
test("")
test([])
test({})
Here is similar code written in Ruby:
def test(value)
if value
print "True"
else
print "False"
end
end
test(0)
test(1)
test("")
test([])
test({})
Let’s compare it to PowerShell:
Function Test($value) {
if ($value) {
Write-Host "True"
} else {
Write-Host "False"
}
}
Test(0)
Test(1)
Test("")
Test(@())
Test(@{})
Same logic in JavaScript for NodeJS:
function test(value) {
if (value) {
console.log("True");
} else {
console.log("False");
}
}
test(0);
test(1);
test("");
test([]);
test({});
Code in PHP:
<?php
function test($value) {
if ($value) {
echo "True";
} else {
echo "False";
}
}
test(0);
test(1);
test("");
test(array());
test(array());
?>
Results are little bit surprising:
|
Python |
Ruby |
PowerShell |
NodeJS |
PHP |
| 0 |
False |
True |
False |
False |
False |
| 1 |
True |
True |
True |
True |
True |
| “” |
False |
True |
False |
False |
False |
| [] |
False |
True |
True |
True |
False |
| {} |
False |
True |
True |
True |
False |
You can test code on-line in Cloud9 IDE except PowerShell example 😉
