Padding 0 on both sides of the PHP string

Str_pad
As the name implies, this function is for a string that can fill any other string with the specified string.

For example: Str_pad (with a filled string, filling the length, filling the string, filling the position)

The length of the fill must be a positive integer, the fill position has three options,
Left: Str_pad_left,
Right: Str_pad_right,
Ends: Str_pad_both

For example:
Echo Str_pad (1, 8, "0″,str_pad_left");
Results: 00000001

Echo Str_pad (1, 8, "0″,str_pad_right");
Results: 10000000

Echo Str_pad (1, 8, "0″,str_pad_both");
Results: 00010000

One of the notable details in the above example is that if the number of digits filled is odd, such as example three fills 7 0, the right priority.

Another way to see Zero is sprintf

This function learned C is very familiar with it, hehe ...

But I do not say so much, because it is too flexible to use, so that I basically do not use, but on the left 0 (or 0 after the decimal point) is very convenient to use.

First look at the left 0
Echo sprintf ("%05d", 1);
First say the meaning of%05d, with a 5-digit number to format the parameters behind, if less than 5 0

Operation result is 00005

Look at the decimal point after 0

Echo sprintf ("%01.3f", 1);

%01.3f means that a minimum of three digits after a decimal point is less than three 0, at least one digit before the decimal point, and a floating-point number that is less than a zero complement is formatted with the parameters behind it.

The operation result is: 1.000

Padding 0 on both sides of the PHP string