Build a tiny version of the Unix grep command. Given a list of lines and a search pattern, return all lines that contain pattern as a substring (case-sensitive), joined by newline characters (\n).
Function signature:
func grep(lines []string, pattern string) string
Example:
Input: pattern = "err" lines = ["error: foo", "warning", "another error", "ok"] Output: "error: foo\nanother error" When printed: error: foo another error
If no lines match, return the empty string "".
Note: real grep treats the pattern as a regular expression by default (grep -F matches plain text). Here the pattern is always plain text: just look for it literally, so characters such as . or * mean nothing special.
Iterate over the lines, keep the ones where
strings.Contains(line, pattern) is true, then return strings.Join(result, "\n").
The full solution:
func grep(lines []string, pattern string) string {
result := []string{}
for _, line := range lines {
if strings.Contains(line, pattern) {
result = append(result, line)
}
}
return strings.Join(result, "\n")
}
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