大约有 3,000 项符合查询结果（耗时：0.0152秒） [XML]
grep using a character vector with multiple patterns
... unique (grep(paste(toMatch,collapse="|"),
myfile$Letter, value=TRUE))
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Drop unused factor levels in a subsetted data frame
... is to apply factor() to your variable again after subsetting:
> subdf$letters
[1] a b c
Levels: a b c d e
subdf$letters <- factor(subdf$letters)
> subdf$letters
[1] a b c
Levels: a b c
EDIT
From the factor page example:
factor(ff) # drops the levels that do not occur
For droppi...
Function to convert column number to letter?
Does anyone have an Excel VBA function which can return the column letter(s) from a number?
28 Answers
...
Laravel Eloquent groupBy() AND also return count of each group
..._info = DB::table('usermetas')
->select('browser', DB::raw('count(*) as total'))
->groupBy('browser')
->get();
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How do I get textual contents from BLOB in Oracle SQL
...xt stored in the BLOB, CS of the database used for VARCHAR2) :
select utl_raw.cast_to_varchar2(dbms_lob.substr(BLOB_FIELD)) from TABLE_WITH_BLOB where ID = '<row id>';
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How do you clear a slice in Go?
... collector.
See playground
package main
import (
"fmt"
)
func dump(letters []string) {
fmt.Println("letters = ", letters)
fmt.Println(cap(letters))
fmt.Println(len(letters))
for i := range letters {
fmt.Println(i, letters[i])
}
}
func main() {
letters := []st...
How to capitalize the first letter in a String in Ruby
...hod capitalizes the entire string, but I need to capitalize only the first letter.
8 Answers
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Getting user input [duplicate]
...
In python 3.x, use input() instead of raw_input()
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Java Naming Convention with Acronyms [closed]
...when possible.
Short Acronyms
The .NET Framework Guidelines say that two letter acronyms like 'IO', should have the same case for both letters. So for PascalCase identifiers (like a class name) you would get DBRate, while for a camelCase identifier (like a local variable) you might have ioChannel....
Insert space before capital letters
...s: /([A-Z]+)/g. The + will make sure you match as many consecutive capital letters as possible.
– iFreilicht
May 18 '17 at 11:18
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