Let’s say you have a bunch of statistical data. \u00a0And all that data is date-related. \u00a0And let’s say want to display that data on a chart, a weekly average or something along those lines. \u00a0One of the ways for you to place the value into the proper week would be something like this:<\/p>\n
\r\n$week = date('W', strtotime($stats_date));\r\n$values[$week][] = $stats_value;\r\n<\/pre>\nAnd if you did it this way, sooner or later, you’d notice that something is not quite working right at the edges of your chart. \u00a0With code as simple and straight-forward as this, you’d probably look for the problem elsewhere. \u00a0Maybe it’s your statistical data which is wrong, or the graph is not generated properly. \u00a0But the problem is here.<\/p>\n
How many weeks do you think there are in a year? \u00a0A common knowledge says 52. \u00a0However, if you think for a moment about how the weeks are related to the year, you’ll realize that the first and last weeks don’t necessary start and end at the edge of the year. \u00a0If you play around with 1st of January and 31st of December across several years, you’ll notice that sometimes they fall into the 53rd week. \u00a0(As do a few more days, not just these two).<\/p>\n
And here, the problem with the “W” date() format starts to emerge. \u00a0 When scattering your data across a single year, you’d most often expect January to start with the first week of the year. \u00a0But it doesn’t. Sometimes the start of it falls into the 53rd week of the previous year. \u00a0And date(‘W’, $your_time)<\/em> will happily return 53. \u00a0What will this do to your chart? \u00a0Two things are most likely. \u00a0The first week’s values would get reduced, and the last week’s values would get increased. \u00a0Or those values of the first week would altogether vanish from the graph. \u00a0That is unless you are careful. \u00a0Which I hope you’ll now be.<\/p>\nSee comments to PHP date() manual<\/a> for several solutions of this problem.<\/p>\n\n","protected":false},"excerpt":{"rendered":"\nLet’s say you have a bunch of statistical data. \u00a0And all that data is date-related. \u00a0And let’s say want to display that data on a chart, a weekly average or something along those lines. \u00a0One of the ways for you to place the value into the proper week would be something like this: $week = … Continue reading PHP date() and 53 weeks<\/span><\/a><\/p>\n\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false,"_links_to":"","_links_to_target":""},"categories":[1,18],"tags":[38,74],"keyring_services":[],"class_list":["post-12125","post","type-post","status-publish","format-standard","hentry","category-general","category-programming","tag-php","tag-tips"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t