如何使用javascript的正则表达式匹配第二个数字？

Question

this is my string.

var id = "timesheet_entries_attributes_0_entry_overtimes_attributes_0_code_id"

question is I want to replace the last zero with another number.

the zero's position is always change. But there are only two zeros in the string. And they can't be together.

such as :

var num = "2"; ("timesheet_entries_attributes_0_entry_overtimes_attributes_0_code_id").replace(/\\d/,num);

but it always replace the first zero.

SoS!

Answer 1

id.replace (/(\d+)(?=\D+$)/, '2')

此版本替换字符串中的LAST数字。

Answer 2

Just a different way to solve:

var id = "timesheet_entries_attributes_0_entry_overtimes_attributes_0_code_id",
    matchIndex = 1,
    replace = 300,
    count = -1;

id = id.replace(/\d+/g, function(number) {
    count++;
    return (count == matchIndex) ? replace : number;
});

demo

Answer 3

var id = "timesheet_entries_attributes_0_entry_overtimes_attributes_0_code_id";
var num_replace = 5;
id = id.replace(/(\d+.*)\d+/, "$1"+num_replace);