Substring

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Definition

Substring

A substring is a contiguous sequence of letters within a string.

For a string $S=a_1{a}_2\dots a_n$, a sequence $a_i{a}_{i+1}\dots a_j$ (where $1\le i\le j\le n$) is a substring.

Examples

Basic Substrings

For the string $S=\text{"banana"}$:

• “ban”
• “ana”
• “nan”
• “a”
• “banana”

Empty String

The empty string $\epsilon$ is a substring of every string.