Havig这样的数据框:
df_in <- data.frame(x = c('x1','x2','x3','x4'),
col1 = c('http://youtube.com/something','NA','https://www.yahooexample.com','https://www.yahooexample2.com'),
col2 = c('https://google.com', 'http://www.bbcnews2.com?id=321','NA','https://google.com/text'),
col3 = c('http://www.bbcnews.com?id=321', 'http://google.com?id=1234','NA','https://bbcnews.com/search'),
col4 = c('NA', 'https://www.youtube/com','NA', 'www.youtube.com/searcht'))
在控制台中打印的数据框输入示例:
x col1 col2 col3 col4 1 x1 http://youtube.com/something https://google.com http://www.bbcnews.com?id=321 NA 2 x2 NA http://www.bbcnews2.com?id=321 http://google.com?id=1234 https://www.youtube/com 3 x3 https://www.yahooexample.com NA NA NA 4 x4 https://www.yahooexample2.com https://google.com/text https://bbcnews.com/search www.youtube.com/searcht
我想创建特定子集条件的数据框。示例我想只保留包含&#34; google&#34;,&#34; youtube&#34;和&#34; bbc&#34;他们的刺痛。 预期产出的例子:
df_out <- data.frame(x = c('x1','x2','x4'),
col1new = c('http://youtube.com/something', 'http://www.bbcnews2.com?id=321', 'https://google.com/text'),
col2new = c('https://google.com', 'http://google.com?id=1234', 'https://bbcnews.com/search'),
col3new = c('http://www.bbcnews.com?id=321', 'https://www.youtube/com', 'www.youtube.com/searcht'))
在控制台中打印的数据框输出示例:
x col1new col2new col3new 1 x1 http://youtube.com/something https://google.com http://www.bbcnews.com?id=321 2 x2 http://www.bbcnews2.com?id=321 http://google.com?id=1234 https://www.youtube/com 3 x4 https://google.com/text https://bbcnews.com/search www.youtube.com/searcht
答案 0 :(得分:2)
我们可以使用grep
创建一个逻辑条件,根据http://
i1 <- Reduce('|', lapply(df_in[-1], grepl, pattern= "https?://(google|youtube|bbc)"))
然后,循环遍历子集数据的行并获取与google/youtube/bbc
tmp <- t(apply(df_in[i1,-1], 1, function(x) x[grepl("(google|youtube|bbc)", x)]))
colnames(tmp) <- paste0('col', seq_len(ncol(tmp)), "new")
和cbind
包含第一列的子集
cbind(df_in[i1, 1, drop = FALSE], tmp)
# x col1new col2new col3new
#1 x1 http://youtube.com/something https://google.com http://www.bbcnews.com?id=321
#2 x2 http://www.bbcnews2.com?id=321 http://google.com?id=1234 https://www.youtube/com
#4 x4 https://google.com/text https://bbcnews.com/search www.youtube.com/searcht