在您使用的包中，searchTwitter函数接受参数since and until，定义在文档如下：
since如果不为 NULL，则将推文限制为自给定日期以来的推文。
日期格式为 YYYY-MM-DD
until如果不为 NULL，则将推文限制为给定日期之前的推文。
日期格式为 YYYY-MM-DD
这就是你所追求的吗？或者如果您想坚持使用userTimeline函数，您可以通过操作来对所需的日期范围进行子集化created的领域status您获得的对象（因此无需使用 Excel）。
EDIT以下是您可以如何对created字段如果您正在使用userTimeline:
library(twitteR)
# get last 100 tweets from the NSF
tweets <- userTimeline('NSF', 100)
# inspect structure of first item in the status object (ie. list of results)
str(tweets[1])
List of 1
$ :Reference class 'status' [package "twitteR"] with 10 fields
..$ text : chr "From the field: Avoiding a Cartography Catastrophe: Study recommends new tools to improve global mapping of inf... http://t.co"| __truncated__
..$ favorited : logi FALSE
..$ replyToSN : chr(0)
..$ created : POSIXct[1:1], format: "2013-02-05 01:43:45"
..$ truncated : logi FALSE
..$ replyToSID : chr(0)
..$ id : chr "298607815617036288"
..$ replyToUID : chr(0)
..$ statusSource: chr "<a href=\"http://twitterfeed.com\" rel=\"nofollow\">twitterfeed</a>"
..$ screenName : chr "NSF"
..and 34 methods, of which 23 are possibly relevant:
.. getCreated, getFavorited, getId, getReplyToSID, getReplyToSN,
.. getReplyToUID, getScreenName, getStatusSource, getText,
.. getTruncated, initialize, setCreated, setFavorited, setId,
.. setReplyToSID, setReplyToSN, setReplyToUID, setScreenName,
.. setStatusSource, setText, setTruncated, toDataFrame, usingMethods
# convert status object to data frame for easier manipulation
tweetsdf <- twListToDF(tweets)
# subset by `created` field, eg get all tweets between 2 Feb and 5 Feb
subset(tweetsdf, created >= as.POSIXct('2013-02-02 00:00:00') & created <= as.POSIXct('2013-02-05 00:00:00'))
这是该子集操作产生的数据框：
text
1 From the field: Avoiding a Cartography Catastrophe: Study recommends new tools to improve global mapping of inf... http://t.co/F6IJ05Sb
2 Video: Research Vessel Sikuliaq launched... and now being prepared for her first Arctic run in 2014, http://t.co/D7GlRnlm
3 Who's watching the power grid? http://t.co/oYsgBl63
4 Ice Melt & the Ice Age... research story on #AAAS #Science Update Daily, featured show @Science360 Radio, http://t.co/XRXSdYL1 #Arctic
5 Taking LIGO to the people http://t.co/R2KHNQTB
6 Pubs: NSF Current - January-February 2013: Available Formats: JSP: http://t.co/2NhEEj6Q... http://t.co/ZSVABpXm
7 Upcoming Due Dates: Interdisciplinary Research in Hazards and Disasters (Hazards SEES): Full Proposal Deadline D... http://t.co/IG3naAFs
8 When children learn to walk, their language improves dramatically http://t.co/FGYXSKu2
favorited replyToSN created truncated replyToSID
1 FALSE NA 2013-02-05 01:43:45 FALSE NA
2 FALSE NA 2013-02-04 19:30:40 FALSE NA
3 FALSE NA 2013-02-04 18:01:33 FALSE NA
4 FALSE NA 2013-02-04 13:55:46 FALSE NA
5 FALSE NA 2013-02-04 13:01:51 FALSE NA
6 FALSE NA 2013-02-02 17:19:30 FALSE NA
7 FALSE NA 2013-02-02 14:25:15 FALSE NA
8 FALSE NA 2013-02-02 14:02:11 FALSE NA
id replyToUID
1 298607815617036288 NA
2 298513923307630592 NA
3 298491499958644736 NA
4 298429645580288000 NA
5 298416076012785666 NA
6 297756138433290240 NA
7 297712287521841156 NA
8 297706485608218624 NA
statusSource
1 <a href="http://twitterfeed.com" rel="nofollow">twitterfeed</a>
2 <a href="http://www.hootsuite.com" rel="nofollow">HootSuite</a>
3 <a href="http://www.hootsuite.com" rel="nofollow">HootSuite</a>
4 <a href="http://www.hootsuite.com" rel="nofollow">HootSuite</a>
5 <a href="http://www.hootsuite.com" rel="nofollow">HootSuite</a>
6 <a href="http://twitterfeed.com" rel="nofollow">twitterfeed</a>
7 <a href="http://twitterfeed.com" rel="nofollow">twitterfeed</a>
8 <a href="http://www.hootsuite.com" rel="nofollow">HootSuite</a>
screenName
1 NSF
2 NSF
3 NSF
4 NSF
5 NSF
6 NSF
7 NSF
8 NSF
