计算字符串中以逗号分隔的值 [英] Count values separated by a comma in a character string

问题描述

我有这个示例数据

d<-"30,3"
class(d)

我在工作数据框中的一列中有这个字符对象，我需要能够识别它有多少个数字.

I have this character objects in one column in my work data frame and I need to be able to identify how many numbers it has.

我尝试使用 length(d)，但它说 1

I have tried to use length(d), but it says 1

在这里寻找解决方案后，我尝试过

After looking for solution here I have tried

eval(parse(text='d'))
as.numeric(d)
as.vector.character(d)

但是还是不行.

有什么简单的方法可以解决这个问题?

Any straightforward approach to solve this problem?

推荐答案

这两种方法都很短，适用于字符串向量，不涉及显式构造拆分字符串的费用，也不使用任何包.这里 d 是一个字符串向量，例如 d <- c("1,2,3", "5,2") :

These two approaches are each short, work on vectors of strings, do not involve the expense of explicitly constructing the split string and do not use any packages. Here d is a vector of strings such as d <- c("1,2,3", "5,2") :

1) count.fields

count.fields(textConnection(d), sep = ",")

2) gregexpr

lengths(gregexpr(",", d)) + 1

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