Why can't switch statements in R language be used in some cases?

data is a data box that I imported from excel. data [6 code 8] gets "Blood"

tem=""
tem==""
switch (tem,
        ="",
        "a"
)

get TRUE , "Blood"

Why are the two cases different?

R
May.09,2021

Please provide a repeatable example

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1c0da0e-323d7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1c0da0e-323d7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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