readarray - split string using IFS delimiter returns empty array

Question

#!/bin/bash
a="2015-05-14 14:55:12.916395602 +0530Ttest_12345"
IFS='T' readarray -t ADDR <<< "$a"
echo "${ADDR[@]:1}"

I am trying to split the string a into time and name using the delimiter T. On printing the first element in the result array ADDR, it prints an empty string however.

How to convert the string with delimiter into array elements?

Answer 1

readarray read lines from standard input into array, so you can do something like this:

$ a="2015-05-14 14:55:12.916395602 +0530Ttest_12345"
$ readarray -t ADDR <<<"$(tr T '\n'<<<"$a")"
$ printf %s\\n "${ADDR[0]}"
2015-05-14 14:55:12.916395602 +0530
$ printf %s\\n "${ADDR[1]}"
test_12345

But you don't need an array at all, you can use parameter expansion:

$ a="2015-05-14 14:55:12.916395602 +0530Ttest_12345"
$ printf %s\\n "${a%T*}"
2015-05-14 14:55:12.916395602 +0530
$ printf %s\\n "${a##*T}"
test_12345

Answer 2

cuonglm's answer is right, you should probably use parameter expansion in that context. However, I though a working example on the use of IFS was missing :

$ IFS=T read -a ADDR <<<"2015-05-14 14:55:12.916395602 +0530Ttest_12345"
$ echo ${ADDR[0]}
2015-05-14 14:55:12.916395602 +0530
$ echo ${ADDR[1]}
test_12345