Question

I need to find two types of instances when there is a “[” character using regular expressions:

1. When the “[” character is followed by a number.
2. When the “[” character is followed by letters.

In Java I have tried:

Pattern firstinstance = Pattern.compile("\\[abcdefgABCDEFG");
Pattern secondinstance = Pattern.compile("\\[[0-9]");

These however, don’t really seem to work. Do you guys have any possible suggestions?

Answer 1

The first instance is when the “[” character is followed by a number.

Any decimal digit in any script:

"\\[\\p{Nd}"

Any digit in 0-9 only:

"\\[\\d"
"\\[[0-9]"

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The second instance is when the “[” character is followed by letters.

Any letter in any script:

"\\[\\p{L}"

Only letters in A-Z or a-z:

"\\[[A-Za-z]"