R将原始数据转换为字符
R convert raw data to character
我尝试将 mongodb 中的 R 加载数据与包 "mongolite" 一起使用，代码如下：
df <- db$find('{}', '{"CurrentId":1,"_id":0}')
其中我要提取集合的"CurrentId"，变量"CurrentId"是mongodb中的ObjectId，其中可能包含多个ObjectId。
和 df 看起来像这样：
[[1]]
list()
[[2]]
list()
[[3]]
list()
[[4]]
list()
[[5]]
list()
[[6]]
[[6]][[1]]
[1] 56 cd 5f 02 b8 9b 5b d0 26 cb 39 c9
[[6]][[2]]
[1] 56 cd 6c 13 b8 9b 5b d0 26 cb 39 d5
[[6]][[3]]
[1] 56 cd 6f c6 b8 9b 5b d0 26 cb 39 de
而df[[6]][[1]]是：
[1] 56 cd 5f 02 b8 9b 5b d0 26 cb 39 c9
typeof(df[[6]][[1]]) 的类型是：
[1] "raw"
我使用paste(dc3[[6]][[1]],collapse = '')将原始类型转换为字符串，就像mongodb ObjectId格式：
[1] "56cd5f02b89b5bd026cb39c9"
然后我尝试像上面那样将 df 中的所有原始数据转换为 string。所以我使用 sapply 函数：
sapply(df, function(x) paste(as.character(x),collapse = ''))
得到这个：
[1] ""
[2] ""
[3] ""
[4] ""
[5] ""
[6] "as.raw(c(0x56, 0xcd, 0x5f, 0x02, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xc9))as.raw(c(0x56, 0xcd, 0x6c, 0x13, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xd5))as.raw(c(0x56, 0xcd, 0x6f, 0xc6, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xde))"
但我想得到这样的东西：
[[1]]
list()
[[2]]
list()
[[3]]
list()
[[4]]
list()
[[5]]
list()
[[6]]
[[6]][[1]]
[1] "56cd5f02b89b5bd026cb39c9"
[[6]][[2]]
[1] "56cd6c13b89b5bd026cb39d5"
[[6]][[3]]
[1] "56cd6fc6b89b5bd026cb39de"
有人知道怎么处理吗？有没有更有效的方法来完成整个工作？
更新：
我应该提供一些代码来重现我的原始数据集：
test = as.raw(as.hexmode(x = c("56","cd","5f","02","b8","9b","5b","d0","26","cb","39","c9")))
df = lapply(1:10,function(x) test)
虽然这段代码产生了这个：
[[1]]
list()
[[2]]
[[2]][[1]]
[1] 5f
[[2]][[2]]
[1] d0
[[3]]
[[3]][[1]]
[1] 26
[[3]][[2]]
[1] 56
[[4]]
list()
[[5]]
[[5]][[1]]
[1] cb
[[6]]
list()
它不像原来的df，但我真的不知道如何将原始数据粘贴到嵌套列表中，希望这对您有所帮助！
sapply(df, function(x) paste(x,collapse = ''))的结果是这样的：
[1] ""
[2] ""
[3] ""
[4] ""
[5] ""
[6] "as.raw(c(0x56, 0xcd, 0x5f, 0x02, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xc9))as.raw(c(0x56, 0xcd, 0x6c, 0x13, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xd5))as.raw(c(0x56, 0xcd, 0x6f, 0xc6, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xde))"
只需使用 paste()，而无需在 sapply() 调用中调用 as.character()。
简短示例：
convertRaw = function(x) paste(x,collapse = '') # works identical in sapply
test = as.raw(as.hexmode(x = c("56","cd","5f","02","b8","9b","5b","d0","26","cb","39","c9"))) # line copied from your sample
convertRaw(test)
[1] "56cd5f02b89b5bd026cb39c9"
更新
实际上还有另一个问题是由使用嵌套列表引起的。由于您处理的是嵌套列表，因此您的 sapply 调用也需要嵌套。您可以即通过 lapply() 调用它。这是一个简短的例子，希望最终能解决您的问题：
test = as.raw(as.hexmode(x = c("56","cd","5f","02","b8","9b","5b","d0","26","cb","39","c9")))
testList = list(list(),list(test,test)) # here I create a short nested list
res = lapply(testList,function(y) sapply(y,function(x) paste(x,collapse = '')))
print(res)
结果是：
[[1]] list()
[[2]] [1] "56cd5f02b89b5bd026cb39c9" "56cd5f02b89b5bd026cb39c9"
如果你喜欢这个：
[[1]] list()
[[2]] [[2]][[1]]
[1] "56cd5f02b89b5bd026cb39c9"
[[2]][[2]]
[1] "56cd5f02b89b5bd026cb39c9"
直接调用，lapply()嵌套：
lapply(testList,function(y) lapply(y,function(x) paste(x,collapse = '')))
我尝试将 mongodb 中的 R 加载数据与包 "mongolite" 一起使用，代码如下：
df <- db$find('{}', '{"CurrentId":1,"_id":0}')
其中我要提取集合的"CurrentId"，变量"CurrentId"是mongodb中的ObjectId，其中可能包含多个ObjectId。
和 df 看起来像这样：
[[1]]
list()
[[2]]
list()
[[3]]
list()
[[4]]
list()
[[5]]
list()
[[6]]
[[6]][[1]]
[1] 56 cd 5f 02 b8 9b 5b d0 26 cb 39 c9
[[6]][[2]]
[1] 56 cd 6c 13 b8 9b 5b d0 26 cb 39 d5
[[6]][[3]]
[1] 56 cd 6f c6 b8 9b 5b d0 26 cb 39 de
而df[[6]][[1]]是：
[1] 56 cd 5f 02 b8 9b 5b d0 26 cb 39 c9
typeof(df[[6]][[1]]) 的类型是：
[1] "raw"
我使用paste(dc3[[6]][[1]],collapse = '')将原始类型转换为字符串，就像mongodb ObjectId格式：
[1] "56cd5f02b89b5bd026cb39c9"
然后我尝试像上面那样将 df 中的所有原始数据转换为 string。所以我使用 sapply 函数：
sapply(df, function(x) paste(as.character(x),collapse = ''))
得到这个：
[1] ""
[2] ""
[3] ""
[4] ""
[5] ""
[6] "as.raw(c(0x56, 0xcd, 0x5f, 0x02, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xc9))as.raw(c(0x56, 0xcd, 0x6c, 0x13, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xd5))as.raw(c(0x56, 0xcd, 0x6f, 0xc6, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xde))"
但我想得到这样的东西：
[[1]]
list()
[[2]]
list()
[[3]]
list()
[[4]]
list()
[[5]]
list()
[[6]]
[[6]][[1]]
[1] "56cd5f02b89b5bd026cb39c9"
[[6]][[2]]
[1] "56cd6c13b89b5bd026cb39d5"
[[6]][[3]]
[1] "56cd6fc6b89b5bd026cb39de"
有人知道怎么处理吗？有没有更有效的方法来完成整个工作？
更新：
我应该提供一些代码来重现我的原始数据集：
test = as.raw(as.hexmode(x = c("56","cd","5f","02","b8","9b","5b","d0","26","cb","39","c9")))
df = lapply(1:10,function(x) test)
虽然这段代码产生了这个：
[[1]]
list()
[[2]]
[[2]][[1]]
[1] 5f
[[2]][[2]]
[1] d0
[[3]]
[[3]][[1]]
[1] 26
[[3]][[2]]
[1] 56
[[4]]
list()
[[5]]
[[5]][[1]]
[1] cb
[[6]]
list()
它不像原来的df，但我真的不知道如何将原始数据粘贴到嵌套列表中，希望这对您有所帮助！
sapply(df, function(x) paste(x,collapse = ''))的结果是这样的：
[1] ""
[2] ""
[3] ""
[4] ""
[5] ""
[6] "as.raw(c(0x56, 0xcd, 0x5f, 0x02, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xc9))as.raw(c(0x56, 0xcd, 0x6c, 0x13, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xd5))as.raw(c(0x56, 0xcd, 0x6f, 0xc6, 0xb8, 0x9b, 0x5b, 0xd0, 0x26, 0xcb, 0x39, 0xde))"
只需使用 paste()，而无需在 sapply() 调用中调用 as.character()。
简短示例：
convertRaw = function(x) paste(x,collapse = '') # works identical in sapply
test = as.raw(as.hexmode(x = c("56","cd","5f","02","b8","9b","5b","d0","26","cb","39","c9"))) # line copied from your sample
convertRaw(test)
[1] "56cd5f02b89b5bd026cb39c9"
更新
实际上还有另一个问题是由使用嵌套列表引起的。由于您处理的是嵌套列表，因此您的 sapply 调用也需要嵌套。您可以即通过 lapply() 调用它。这是一个简短的例子，希望最终能解决您的问题：
test = as.raw(as.hexmode(x = c("56","cd","5f","02","b8","9b","5b","d0","26","cb","39","c9")))
testList = list(list(),list(test,test)) # here I create a short nested list
res = lapply(testList,function(y) sapply(y,function(x) paste(x,collapse = '')))
print(res)
结果是：
[[1]] list()
[[2]] [1] "56cd5f02b89b5bd026cb39c9" "56cd5f02b89b5bd026cb39c9"
如果你喜欢这个：
[[1]] list()
[[2]] [[2]][[1]]
[1] "56cd5f02b89b5bd026cb39c9"
[[2]][[2]]
[1] "56cd5f02b89b5bd026cb39c9"
直接调用，lapply()嵌套：
lapply(testList,function(y) lapply(y,function(x) paste(x,collapse = '')))