在for循环中增加一个值

Question

I have the following code for for loop, what I am trying to do is each time the loop runs the next $data needs to be the previous $data * 1.025

$amount = 3150;
$age=22;
for ($x = $age; $x<= 60; $x++){
    $data = $amount*1.025;
    echo "amount_$x = $data<br>";
}

This gives me the following outcome, which is understood because the value of $data never changes

amount_22 = 3228.75
amount_23 = 3228.75
amount_24 = 3228.75
amount_25 = 3228.75

where as the outcome i am looking for should be something like

amount_22 = 3228.75
amount_23 = 3309.47
amount_24 = 3392.20
amount_25 = 3477.01

I will appreciate any help in how to get the next value of $data * 1.025

Answer 1

$amount doesn't change in your loop, so $amount*1.025; doesn't change either. Try $data = $data*1.025; . Note you'll need to initialize $data = $amount; .

Answer 2

You are changing $data based on the same variable $amount . Amount does not change in the loop, so the result is the same.

Try this:

$amount = 3150;
$age = 22;
for ($x = $age; $x <= 60; $x++){
    $amount = $amount*1.025;
    echo "amount_$x = $amount<br>";
}

Answer 3

Try changing the code to this:

$amount = $amount*1.025;
echo "amount_$x = $amount<br>";

This will increment the amount each time, and changes will be retained since amount is declared outside the loop.

Answer 4

Update $amount with each loop.

Eg

$amount = 3150;
$age=22;
for ($x = $age; $x<= 60; $x++){
    $amount = $amount*1.025;
    echo "amount_$x = $amount<br>";
}

Answer 5

You said the new data has to be the previous data * 1.025, but you're multiplying $amount instead of $data .

$data = 3150;
$age=22;
for ($x = $age; $x<= 60; $x++){
    $data = $data*1.025;
    echo "amount_$x = $data<br>";
}

Answer 6

A sweet solution is to assign a variable of the product of $amount and 1.025 for iteration so:

<?php

$amount = 3150;
$age=22;

for ($x = $age; $x<= 60; $x++){
    $amount = $amount * 1.025;
    echo "amount_$x = $amount<br>";
}
?>