How PHP implements the substitution of strings

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Substr_replace (String,replacement,start,length)

The first argument is: the string to replace ( required )

The second argument is: Specify the string to replace ( required )

The third parameter is: Where to start the replacement ( required )

Positive number-begins the substitution at the specified position in the string
Negative number-replaces at the specified position from the end of the string

0-Start the substitution at the first character in the string

Fourth parameter: Specifies how many characters to replace ( optional )

Positive number-The length of the string being replaced
Negative-Indicates the number of characters at the end of the substring to be replaced.

0-Insert rather than replace

Cases:

$str = ' 220282198801011234 '; $new _str = Substr_replace ($str, ' ******** ', 6,8);p Rint_r ($new _str);

Print as follows:

220282******1234

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