blocks|key|900383|text|如果没有可重复的示例，很难确切知道您要查找的是什么，但是dplyr::select()有几个用于选择列的选项，而dplyr::everything()可能就是您要查找的列：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|900384|library(dplyr)

#+this+reorders+the+column+names,+but+keeps+everything+without+having+to+name+the+columns+specifically:
mtcars+%25>%25+
++select(carb,+gear,+everything())+

#+from+a+list+of+column+names:
keep_columns+<-+c('cyl','disp','hp')
mtcars+%25>%25+
++select(one_of(keep_columns))+

#+specific+names,+and+a+range+of+names:
mtcars+%25>%25+
++select(hp,+qsec:gear)+

#You+could+also+use++`contains()`,+`starts_with()`,+`ends_with()`,+or+`matches()`.+Note+that+calling+all+of+the+following+at+once+will+give+you+no+results:
mtcars+%25>%25+
++select(contains('t'))+%25>%25
++select(starts_with('a'))+%25>%25+
++select(ends_with('b'))+%25>%25+
++select(matches('%5Em.%2Bg$'))+|code-block|syntax|javascript|900385|entityMap^0|S|F|1K|J|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

Without a reproducible example, it's difficult to know what exactly you're looking for, but <code>dplyr::select()</code> has several options for selecting columns, and <code>dplyr::everything()</code> might be what you're looking for:

<pre><code>library(dplyr)

# this reorders the column names, but keeps everything without having to name the columns specifically:
mtcars %&gt;% 
 select(carb, gear, everything()) 

# from a list of column names:
keep_columns &lt;- c('cyl','disp','hp')
mtcars %&gt;% 
 select(one_of(keep_columns)) 

# specific names, and a range of names:
mtcars %&gt;% 
 select(hp, qsec:gear) 

#You could also use `contains()`, `starts_with()`, `ends_with()`, or `matches()`. Note that calling all of the following at once will give you no results:
mtcars %&gt;% 
 select(contains('t')) %&gt;%
 select(starts_with('a')) %&gt;% 
 select(ends_with('b')) %&gt;% 
 select(matches('^m.+g$')) 
</code></pre>

blocks|key|1220294|text|控制台回复的方式(+%2B指示它正在等待表达式的其余部分)强烈地表明，您遇到的是控制台处理长命令(您试图通过从剪贴板粘贴来组装)的容量限制，而不是可以选择的列数的固有限制。在文档中，我能找到的唯一有此限制的地方是here，它写着“在控制台输入的命令行限于大约4095字节”。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1220295|在注释中，您说要选择的列名位于csv文件中。您没有过多地介绍csv文件的结构，但是假设您有一个包含单个列名列表的csv文件。作为示例，我创建了一个名为"colnames.csv"的文件，该文件只有一行：|1220296|Sepal.Width,+Petal.Length|code-block|syntax|javascript|1220297|请注意，不需要在文本文件中的列名两边手动放置引号。然后在R控制台中输入：|1220298|iris+%25>%25+select(one_of(as.character(read.csv("colnames.csv",header+=+FALSE,+strip.white+=+TRUE,stringsAsFactors+=+FALSE))))|1220299|它的工作效果与预期一致。尽管这个示例只使用了2列，但对于3000%2B，它没有理由失败，因为列数本身并不是您所做的事情的问题。|1220300|如果csv文件的结构与示例不同，那么您将需要调整对read.csv的调用，也许还需要调整将其转换为字符向量的方式，但您应该能够根据您的情况调整这种方法。|1220301|entityMap|0|LINK|mutability|MUTABLE|url|https://cran.r-project.org/doc/manuals/R-intro.html#Using-R-interactively^0|A|1|2W|4|0|0|23|E|0|0|0|0|0|P|8|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1B|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1C|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|1D|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1E|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|1F|8|@$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|V|$W|$5|X|Y|Z|E|$10|11]]]]

The way that the console replies (with the <code>+</code> indicating that it is waiting for the rest of the expression) strongly suggests that you are encountering a limitation in the capacity for the console to process long commands (which you are attempting to assemble via pasting from the clipboard) rather than an inherent limit in the number of columns which can be selected. The only place I could find in the documentation to this limitation is <a href="https://cran.r-project.org/doc/manuals/R-intro.html#Using-R-interactively" rel="nofollow noreferrer">here</a> where it says "Command lines entered at the console are limited to about 4095 bytes."

In the comments you said that the column names that you wanted to select were in a csv file. You didn't say much about the structure of the csv file, but say that you have a csv file that contains a single list of column names. As an example, I created a file named <code>"colnames.csv"</code> which has a single line:

<pre><code>Sepal.Width, Petal.Length
</code></pre>

Note that there is no need to manually place quote marks around the column names in the text file. Then in the R console I typed:

<pre><code>iris %&gt;% select(one_of(as.character(read.csv("colnames.csv",header = FALSE, strip.white = TRUE,stringsAsFactors = FALSE))))
</code></pre>

which worked as expected. Even though this example only used 2 columns, there is no reason that it should fail with 3000+, since the number of columns per se wasn't the problem with what you were doing.

If the structure of the csv file is different from the example then you would need to adjust the call to <code>read.csv</code> and perhaps the way that you convert it to a character vector, but you should be able to tweak this approach to your situation.

I want to select 3117 columns out of a data frame,
I tried to select them by column names:

<pre><code>dataframe %&gt;% 
 select(
 'AAACCTGAGCACGCCT-1',
 'AAACCTGAGCGCTTAT-1',
 'AAACCTGAGCGTTGCC-1',
 ......,
 'TTGGAACCACGGACAA-1'
 )
</code></pre>

or

<pre><code>firstpickupnames &lt;- ('AAACCTGAGCACGCCT-1','AAACCTGAGCGCTTAT-1','AAACCTGAGCGTTGCC-1',......,'TTGGAACCACGGACAA-1')
</code></pre>

Both ways the R console just replied 

<pre><code>'AAACCTGAGCACGCCT-1','AAACCTGAGCGCTTAT-1','AAACCTGAGCGTTGCC-
1',......,'TTGGAACCACGGACAA-1'
+ )
+
</code></pre>

What does this mean? Is there a limitation of columns that I can select in R?

How many columns can be selected in a data frame in R?

我想从数据框中选择3117列，我尝试按列名选择它们：dataframe %>%   select(    'AAACCTGAGCACGCCT-1',    'AAACCTGAGCGCTTAT-1',    'AAACCTGAGCGTTGCC-1',    ......,    'TTGGAACCACGGACAA-1' ...

问在R中的一个数据框中可以选择多少列？
EN

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问在R中的一个数据框中可以选择多少列？
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