我有一个数据帧，我想在其中将包含值"2018"的列中的所有值替换为 NULL。
我有一个数据集，其中列中的每个值都是一个列表。还包括空值。其中一个值不是列表，我想用 NULL 替换它。如果我用 NA 替换它，那么该列中的数据类型是混合的。
如果我有如下所示的列，如何将包含 2018 的值替换为 NULL 而不是 NA？
spend actions
176.2 2018-02-24
166.66 list(action_type = c("landing_page_view", "link_click", "offsit...
153.89 list(action_type = c("landing_page_view", "like", "link_click",...
156.54 list(action_type = c("landing_page_view", "like", "link_click",...
254.95 list(action_type = c("landing_page_view", "like", "link_click",...
374 list(action_type = c("landing_page_view", "like", "link_click",...
353.29 list(action_type = c("landing_page_view", "like", "link_click",...
0.41 NULL
可重现的示例：
structure(list(spend = c("176.2", "166.66", "153.89", "156.54",
"254.95", "374", "353.29", "0.41"), actions = list("2018-02-24",
structure(list(action_type = c("landing_page_view", "link_click",
"offsite_conversion.fb_pixel_add_to_cart",
"offsite_conversion.fb_pixel_purchase",
"offsite_conversion.fb_pixel_search",
"offsite_conversion.fb_pixel_view_content",
"post", "post_reaction", "page_engagement", "post_engagement",
"offsite_conversion"), value = c("179", "275", "212", "18",
"269", "1434", "1", "17", "293", "293", "1933")), .Names = c("action_type",
"value"), class = "data.frame", row.names = c(NA, 11L)),
structure(list(action_type = c("landing_page_view", "like",
"link_click", "offsite_conversion.fb_pixel_add_to_cart",
"offsite_conversion.fb_pixel_purchase",
"offsite_conversion.fb_pixel_search",
"offsite_conversion.fb_pixel_view_content", "post_reaction",
"page_engagement", "post_engagement", "offsite_conversion"
), value = c("136", "3", "248", "101", "6", "237", "730",
"11", "262", "259", "1074")), .Names = c("action_type", "value"
), class = "data.frame", row.names = c(NA, 11L)), structure(list(
action_type = c("landing_page_view", "like", "link_click",
"offsite_conversion.fb_pixel_add_to_cart",
"offsite_conversion.fb_pixel_purchase",
"offsite_conversion.fb_pixel_search",
"offsite_conversion.fb_pixel_view_content",
"post", "post_reaction", "page_engagement", "post_engagement",
"offsite_conversion"), value = c("95", "1", "156", "91",
"5", "83", "532", "1", "13", "171", "170", "711")), .Names =
c("action_type",
"value"), class = "data.frame", row.names = c(NA, 12L)),
structure(list(action_type = c("landing_page_view", "like",
"link_click", "offsite_conversion.fb_pixel_add_to_cart",
"offsite_conversion.fb_pixel_purchase",
"offsite_conversion.fb_pixel_search",
"offsite_conversion.fb_pixel_view_content", "post_reaction",
"page_engagement", "post_engagement", "offsite_conversion"
), value = c("178", "4", "243", "56", "4", "138", "437",
"19", "266", "262", "635")), .Names = c("action_type", "value"
), class = "data.frame", row.names = c(NA, 11L)), structure(list(
action_type = c("landing_page_view", "like", "link_click",
"offsite_conversion.fb_pixel_add_to_cart",
"offsite_conversion.fb_pixel_purchase",
"offsite_conversion.fb_pixel_search",
"offsite_conversion.fb_pixel_view_content",
"post_reaction", "page_engagement", "post_engagement",
"offsite_conversion"), value = c("203", "2", "306", "105",
"7", "186", "954", "23", "331", "329", "1252")), .Names =
c("action_type",
"value"), class = "data.frame", row.names = c(NA, 11L)),
structure(list(action_type = c("landing_page_view", "like",
"link_click", "offsite_conversion.fb_pixel_add_to_cart",
"offsite_conversion.fb_pixel_purchase",
"offsite_conversion.fb_pixel_search",
"offsite_conversion.fb_pixel_view_content", "post", "post_reaction",
"page_engagement", "post_engagement", "offsite_conversion"
), value = c("241", "4", "320", "106", "3", "240", "789",
"1", "17", "342", "338", "1138")), .Names = c("action_type",
"value"), class = "data.frame", row.names = c(NA, 12L)),
NULL)), .Names = c("spend", "actions"), row.names = c(NA,
-8L), class = "data.frame")
我的最终目标是将此函数与此数据集一起使用，使action_types成为自己的列。当列表或 NULL 位于操作列中时，此函数有效：
fb_insights_all<-df %>%
as.tibble() %>%
filter(!map_lgl(actions, is.null)) %>%
unnest() %>%
right_join(select(df, -actions)) %>%
spread(action_type, value)
Error: Each column must either be a list of vectors or a list of data frames [actions]
如果没有数据来测试这一点，我会尝试：
df$COL1<-ifelse(grepl("2018", df$COL1),"NULL",df$COL1)
如此处所述，NA 的功能更像您似乎正在尝试执行的操作，而 NULL 则提供不同的功能。如果只想让值只说"NULL"，而不是像 NULL 那样函数，请将其视为字符值。