strings.isLetter() function

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strings.isLetter() tests if a single character string is a letter (a-z, A-Z).

Function type signature

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Parameters

v

({{< req >}}) Single-character string to test.

Examples

Filter by columns with digits as values

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Input data

_time	_value	*tag
2021-01-01T00:00:00Z	s	t1
2021-01-01T00:00:10Z	n	t1
2021-01-01T00:00:20Z	4	t1
2021-01-01T00:00:30Z	4	t1
2021-01-01T00:00:40Z	e	t1
2021-01-01T00:00:50Z	y	t1

_time	_value	*tag
2021-01-01T00:00:00Z	a	t2
2021-01-01T00:00:10Z	p	t2
2021-01-01T00:00:20Z	4	t2
2021-01-01T00:00:30Z	t	t2
2021-01-01T00:00:40Z	7	t2
2021-01-01T00:00:50Z	v	t2

Output data

_time	_value	*tag
2021-01-01T00:00:00Z	s	t1
2021-01-01T00:00:10Z	n	t1
2021-01-01T00:00:40Z	e	t1
2021-01-01T00:00:50Z	y	t1

_time	_value	*tag
2021-01-01T00:00:00Z	a	t2
2021-01-01T00:00:10Z	p	t2
2021-01-01T00:00:30Z	t	t2
2021-01-01T00:00:50Z	v	t2

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