[英]drop a digit for some data points in a column in R
I have a column of numbers (characters) which has either 8 digits or 9 digits data.我有一列数字(字符),其中包含 8 位或 9 位数据。 If the data point has 9 digits, I want to drop the first digit.如果数据点有 9 位数字,我想删除第一个数字。 I'm using the following command:我正在使用以下命令:
file$hscode2 <- if (nchar(file$hscode1 >= 9)) {
file$hscode2 <- substr(file$hscode1,2,9)
}
where the data frame is "file" and the column with 8/9 digits data is hscode1 and the new column which drops the first digit when it is 9 digit character is hscode2其中数据框是“文件”,具有 8/9 位数据的列是 hscode1,当它是 9 位字符时删除第一个数字的新列是 hscode2
However, I'm not getting the desired result.但是,我没有得到想要的结果。 Any suggestions?有什么建议?
Thanks谢谢
I think there is a bug.我认为有一个错误。 It should be:它应该是:
file$hscode2 <- if (nchar(file$hscode1) >= 9) {
file$hscode2 <- substr(file$hscode1,2,9)
}
As written, your function was running nchar on "file$hscode1 >= 9" which is a boolean, which if converted to a char would just be 1 character, hence the conditions would always have been true I think (leading to the unexpected results you were seeing).如所写,您的函数在 "file$hscode1 >= 9" 上运行 nchar,这是一个布尔值,如果转换为 char 将只是 1 个字符,因此我认为条件始终为真(导致意外结果你看到了)。
As suggested by @missuse, ifelse()
will work fine here.正如@missuse 所建议的, ifelse()
在这里可以正常工作。
file$hscode2 <- ifelse(nchar(file$hscode1 >= 9), # test
substr(file$hscode1, 2, 9), # value if true
file$hscode1) # value if false
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