{"id":33,"date":"2009-04-06T18:10:08","date_gmt":"2009-04-06T12:40:08","guid":{"rendered":"https:\/\/tothenewco.pro\/blog\/?p=33"},"modified":"2016-12-19T15:28:29","modified_gmt":"2016-12-19T09:58:29","slug":"groovy-collection-method-groupby","status":"publish","type":"post","link":"https:\/\/tothenewco.pro\/blog\/groovy-collection-method-groupby\/","title":{"rendered":"Groovy Collection method: groupBy()"},"content":{"rendered":"

public Map groupBy(Closure closure)<\/code><\/p>\n

Going through Groovy Collection, I found this powerful method which takes a Closure as parameter & based on the closure, it returns a map in which all unique values returned by closure act as keys.<\/p>\n

Lets take an example:<\/p>\n

If you want to group integers between 1 to 100 based on the integer value at units place as follows:<\/p>\n

[1:[1, 11, 21, 31, 41, 51, 61, 71, 81, 91],\r\n2:[2, 12, 22, 32, 42, 52, 62, 72, 82, 92],\r\n3:[3, 13, 23, 33, 43, 53, 63, 73, 83, 93],\r\n4:[4, 14, 24, 34, 44, 54, 64, 74, 84, 94],\r\n5:[5, 15, 25, 35, 45, 55, 65, 75, 85, 95],\r\n6:[6, 16, 26, 36, 46, 56, 66, 76, 86, 96],\r\n7:[7, 17, 27, 37, 47, 57, 67, 77, 87, 97],\r\n8:[8, 18, 28, 38, 48, 58, 68, 78, 88, 98],\r\n9:[9, 19, 29, 39, 49, 59, 69, 79, 89, 99],\r\n0:[10, 20, 30, 40, 50, 60, 70, 80, 90, 100]]<\/pre>\n
Just think of the code you will need to write in Java for this.<\/p>\n
However, its a single method call in Groovy:    (1..100).groupBy{it%10}<\/code><\/p>\n
Hope to find more such methods over time.<\/p>\n
\u2013
\n~Aman Aggarwal
\naman@intelligrape.com<\/p>\n
http:\/\/www.IntelliGrape.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
public Map groupBy(Closure closure) Going through Groovy Collection, I found this powerful method which takes a Closure as parameter & based on the closure, it returns a map in which all unique values returned by closure act as keys. Lets take an example: If you want to group integers between 1 to 100 based on […]<\/p>\n","protected":false},"author":282,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":81,"footnotes":""},"categories":[7],"tags":[4840,9],"class_list":["post-33","post","type-post","status-publish","format-standard","hentry","category-grails","tag-grails","tag-groovy"],"aioseo_notices":[],"aioseo_head":"\n\t\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