如何将年份字符串转换为PHP中的日期？

Question

I am trying to convert a string into a date. Specifically, a string of a year into a date.

strtotime('2017') // Gives us -> 1517372220

$year = '2017';
var_dump($year); // '2017'
$year = date("Y", strtotime($year));
var_dump($year); // '2018' 

Why is the date method defaulting to the current time? I am passing an integer.

According to the documentation, I seem to implementing this method correctly?

string date ( string $format [, int $timestamp = time() ] )

The optional timestamp parameter is an integer Unix timestamp that defaults to the current local time if a timestamp is not given. In other words, it defaults to the value of time().

Answer 1

Based on strtotime() Manual

strtotime — Parse about any English textual datetime description into a Unix timestamp

Parameters

time-> A date/time string. Valid formats are explained in Date and Time Formats.

So either you need to provide a textual representation or a valid date format (not only years).

So code need to be like this:-

<?php

$year = date("Y", strtotime('2017-01-01'));
var_dump($year); // '2018' 

Output:- https://eval.in/945561

Reference:- valid formats for strtotime()