{"action":"closed","issue":{"url":"https://api.github.com/repos/Rdatatable/data.table/issues/1600","repository_url":"https://api.github.com/repos/Rdatatable/data.table","labels_url":"https://api.github.com/repos/Rdatatable/data.table/issues/1600/labels{/name}","comments_url":"https://api.github.com/repos/Rdatatable/data.table/issues/1600/comments","events_url":"https://api.github.com/repos/Rdatatable/data.table/issues/1600/events","html_url":"https://github.com/Rdatatable/data.table/issues/1600","id":141976545,"number":1600,"title":"fread changing values","user":{"login":"jvondollen","id":2341664,"avatar_url":"https://avatars.githubusercontent.com/u/2341664?v=3","gravatar_id":"","url":"https://api.github.com/users/jvondollen","html_url":"https://github.com/jvondollen","followers_url":"https://api.github.com/users/jvondollen/followers","following_url":"https://api.github.com/users/jvondollen/following{/other_user}","gists_url":"https://api.github.com/users/jvondollen/gists{/gist_id}","starred_url":"https://api.github.com/users/jvondollen/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jvondollen/subscriptions","organizations_url":"https://api.github.com/users/jvondollen/orgs","repos_url":"https://api.github.com/users/jvondollen/repos","events_url":"https://api.github.com/users/jvondollen/events{/privacy}","received_events_url":"https://api.github.com/users/jvondollen/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/Rdatatable/data.table/labels/not%20reproducible","name":"not reproducible","color":"f7c6c7"}],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2016-03-18T20:59:03Z","updated_at":"2016-03-18T21:09:14Z","closed_at":"2016-03-18T21:09:14Z","body":"When reading in a dataset, I've come across the famous warning message about \"bumping\" columns to type character. In some cases, this results in the values in the column getting converted to something else.  An example is reading in a tab delimited txt file such as:\r\n\r\n| Run | label |\r\n| --- | ----- |\r\n| 2 | T |\r\n| 3 | T |\r\n| 4 | T |\r\n| 5 | T |\r\n| 6 | T |\r\n| 7 | T |\r\n| 9 | T |\r\n| 10 | T |\r\n| 1 | C |\r\n| 8 | C |\r\n| 11 | T |\r\n| 12 | T |\r\n| 13 | T |\r\n| 14 | T |\r\n| 15 | T |\r\n| 16 | T |\r\n| 17 | T |\r\n| 18 | T |\r\n| 20 | T |\r\n| 21 | T |\r\n| 22 | T |\r\n| 23 | T |\r\n| 25 | T |\r\n| 19 | C |\r\n| 24 | C |\r\n| 32 | C |\r\n| 26 | T |\r\n| 27 | T |\r\n| 28 | T |\r\n| 29 | T |\r\n| 30 | T |\r\n| 31 | T |\r\n| 33 | T |\r\n| 34 | T |\r\n| 35 | T |\r\n| 36 | T |\r\n| 37 | T |\r\n| 38 | T |\r\n| 39 | T |\r\n\r\n\r\nThe warning pops up and says that column two has been bumped to type character. When we look at the resulting data.table object read in, the first portion of the column has been changed from T's to numeric 1's instead:\r\n\r\n|  | Run | label |\r\n| --- | --- | ----|\r\n| 1: | 2 | 1 |\r\n| 2: | 3 | 1 |\r\n| 3: | 4 | 1 |\r\n| 4: | 5 | 1 |\r\n| 5: | 6 | 1 |\r\n| 6: | 7 | 1 |\r\n| 7: | 9 | 1 |\r\n| 8: | 10 | 1 |\r\n| 9: | 1 | C |\r\n| 10: | 8 | C |\r\n| 11: | 11 | T |\r\n| 12: | 12 | T |\r\n| 13: | 13 | T |\r\n| 14: | 14 | T |\r\n| 15: | 15 | T |\r\n| 16: | 16 | T |\r\n| 17: | 17 | T |\r\n| 18: | 18 | T |\r\n| 19: | 20 | T |\r\n| 20: | 21 | T |\r\n| 21: | 22 | T |\r\n| 22: | 23 | T |\r\n| 23: | 25 | T |\r\n| 24: | 19 | C |\r\n| 25: | 24 | C |\r\n| 26: | 32 | C |\r\n| 27: | 26 | T |\r\n| 28: | 27 | T |\r\n| 29: | 28 | T |\r\n| 30: | 29 | T |\r\n| 31: | 30 | T |\r\n| 32: | 31 | T |\r\n| 33: | 33 | T |\r\n| 34: | 34 | T |\r\n| 35: | 35 | T |\r\n| 36: | 36 | T |\r\n| 37: | 37 | T |\r\n| 38: | 38 | T |\r\n| 39: | 39 | T |\r\n\r\nI get these warnings all the time for different datasets, and I'm scared to think about what data has been changed by using fread. \r\n\r\nR version 3.2.3 (2015-12-10)\r\nPlatform: x86_64-apple-darwin13.4.0 (64-bit)\r\nRunning under: OS X 10.9.5 (Mavericks)\r\ndata.table Version 1.9.6\r\n\r\n"}}