I am looking to do something very similar to the following PHP code but in javascipt:
for ($weenumber = 1; $weenumber <= 30; $weenumber++)
{
$weenumber = str_pad($weenumber, 2, "0", STR_PAD_LEFT);
echo $_POST["entry{$weenumber}_cash"];
}
Basically accessing the loop number padded with a trailing 0 if less than 10 but I dont know the syntax in JS to do this :(
Sorry for noob style question
I think that you mean a leading zero rather than a trailing zero...
You can for example use the conditional operator:
(n < 10 ? '0' : '') + n
You could also implement a general purpose function:
function padLeft(str, len, ch) {
while (str.length < len) str = ch + str;
return str;
}
To access an object property by name in Javascript you use brackets. Example:
var value = obj['entry' + (n < 10 ? '0' : '') + n + '_cash'];
If n contains 4, this will be the same as obj.entry04_cash.
Whether or not there's a specific function to do this, if you know how to use an if clause, and you know how to perform string concatentation (using the + operator if you didn't), then you should be able to easily roll you own version of str_pad by hand (which works for numbers below 100).
Think about the cases involved (there are only two) and what you need to output in either case.
This is the code you should use:
for(var i=0; i<30; i++){
document.writeln(i<10 ? "0"+i : i);
}
change document.writeln() with any function you want to handle the data
for (weenumber = 1; weenumber <= 30; weenumber++) {
weenumber = str_pad(weenumber, 2, "0", STR_PAD_LEFT);
}
For the str_pad() function, you can use PHPJS library: http://phpjs.org/functions/str_pad:525
This library will also ease transition from php to javascript for you. Check it out.
for(var i=0; i<30; i++)
{
var index = i;
if(i<10) index = "0" + index
var elem = document.getElementById("entry"+index);
}
var someArray = [/*...*/];
for (var i= 1;i<= 30;i++)
{
var weenumber = i+"";
for(var j=weenumber.length;j<2;j++)
weenumber = "0" + weenumber;
var key = "entry" + weenumber + "_cash";
document.write(someArray[key]);
}
Here's a function you can use for zeropadding:
function zeroPad(nr,base){
var len = (String(base).length - String(nr).length)+1;
return len > 0? new Array(len).join('0')+nr : nr;
}
//usage
alert(zeroPad(3,10)); //=> 03
or extend the Number prototype
Number.prototype.zeroPad = Number.prototype.zeroPad ||
function(base){
var nr = this, len = (String(base).length - String(nr).length)+1;
return len > 0? new Array(len).join('0')+nr : nr;
};
//usage
var num = 1;
alert(num.zeroPad(100)); //=> 001
Now for the variable name part: if it's a global variable (not advisable) that variable is a property of the global object, in a browser that's window. You can get a variable by its dynamic name using the equivalent of: window['myvariable'+myJustResolvedNumericValue]. Within an object (instance) you can use the same bracket notation: myObject['myvariable'+myJustResolvedNumericValue].
Using this information, in javascript your function could look like:
for (var weenumber = 1; weenumber <= 30; weenumber++)
{
// execute something using the variable that uses the counter in the
// variable name as parameter
executeSomeFunction(window['entry'+weenumber.padLeft(10) + '_cash']);
}
0if less than 10", right?