Method: Polars::StringExpr#zfill

Defined in:
lib/polars/string_expr.rb

#zfill(length) ⇒ Expr

Fills the string with zeroes.

Return a copy of the string left filled with ASCII '0' digits to make a string of length width.

A leading sign prefix ('+'/'-') is handled by inserting the padding after the sign character rather than before. The original string is returned if width is less than or equal to s.length.

Examples:

df = Polars::DataFrame.new({"a" => [-1, 123, 999999, nil]})
df.with_columns(Polars.col("a").cast(Polars::String).str.zfill(4).alias("zfill"))
# =>
# shape: (4, 2)
# ┌────────┬────────┐
# │ a      ┆ zfill  │
# │ ---    ┆ ---    │
# │ i64    ┆ str    │
# ╞════════╪════════╡
# │ -1     ┆ -001   │
# │ 123    ┆ 0123   │
# │ 999999 ┆ 999999 │
# │ null   ┆ null   │
# └────────┴────────┘

Parameters:

  • length (Integer) —

    Fill the value up to this length

Returns:



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# File 'lib/polars/string_expr.rb', line 747

def zfill(length)
  length = Utils.parse_into_expression(length)
  Utils.wrap_expr(_rbexpr.str_zfill(length))
end