Strings

upper, lower, trim, replace, split, join, printf and friends.

The string builtins. Most are callable as a function, a pipe target, or (where the arity allows) a method. The standard squiggly convention is data-last: in pipe form s | trim becomes trim s, in s | replace 'a' 'b' it becomes replace 'a' 'b' s. The tables below list the function-call signature in left-to-right order; pipe form threads the piped value in as the last argument.

Case & whitespace

Function	Arity	Signature	What
`upper`	1	`upper s`	Uppercase
`lower`	1	`lower s`	Lowercase
`capitalize`	1	`capitalize s`	Uppercase the first letter
`trim`	1	`trim s`	Strip leading + trailing whitespace
`ltrim`	1	`ltrim s`	Strip leading whitespace only
`rtrim`	1	`rtrim s`	Strip trailing whitespace only
`newline_to_br`	1	`newline_to_br s`	Replace `\n` with `<br />`

Predicates & search

Function	Arity	Signature	What
`length`	1	`length s`	Number of characters (works on lists / maps too)
`isEmpty`	1	`isEmpty s`	True iff length is zero
`nonEmpty`	1	`nonEmpty s`	True iff length is non-zero
`startsWith`	2	`startsWith prefix s`	True iff `s` starts with `prefix`
`endsWith`	2	`endsWith suffix s`	True iff `s` ends with `suffix`
`contains`	2	`contains needle s`	True iff `s` contains `needle`

Slicing & shaping

Function	Arity	Signature	What
`reverse`	1	`reverse s`	Reverse the string
`substring`	2/3	`substring from s` / `substring from until s`	Half-open slice; `from`/`until` are character indices
`truncate`	2/3	`truncate n s` / `truncate n ellipsis s`	Truncate to `n` words; appends ellipsis (default `…`) when shortened
`split`	2	`split sep s`	Split on a literal separator; returns a list

Editing

Function	Arity	Signature	What
`replace`	3	`replace old new s`	Replace every occurrence of `old` with `new`
`remove`	2	`remove substr s`	Drop every occurrence of `substr`
`removeFirst`	2	`removeFirst substr s`	Drop only the first occurrence of `substr`
`htmlEscape`	1	`htmlEscape s`	Escape `&<>'"` for safe HTML embedding

Formatted output

Function	Arity	Signature	What
`printf`	1+	`printf fmt args...`	Format-string output (Java `Formatter` rules: `%d` / `%05d` / `%,d` / `%.2f` / `%-10s` / `%x` / `%%`)

Examples

{{ .title | upper }}                              CSS HOOK
{{ .author | trim | lower | replace ' ' '-' }}    "ed-maxedon"
{{ .body | split '\n' | length }}                 number of lines

{{ if .filename | endsWith '.md' }}               markdown file
{{ if .body | contains '<!--more-->' }}           has a manual summary cut

{{ split ',' .csv | join ' / ' }}                 reformat

{{ printf '%05d' .count }}                        zero-padded
{{ printf '%,d' .revenue }}                       1,234,567
{{ printf '%-10s|%s' .key .value }}               left-pad first column