ljust

ljust is a string method in Python that returns a left-justified version of the string within a field of a specified width. The result is padded on the right with a fill character (by default a space). The method does not modify the original string but returns a new string.

Syntax and parameters: the method is called as s.ljust(width[, fillchar]). width is an integer that defines the total length of the returned string. If width is less than or equal to the length of s, the original string s is returned unchanged. fillchar is an optional single-character string used to pad on the right; if not provided, a space is used by default. If fillchar is provided but has length not equal to 1, Python raises a TypeError indicating that the fill character must be exactly one character long.

Return value: a new string that has length equal to width. If width exceeds the length of s, the string is padded on the right with fillchar until the total length matches width. If width is not an integer or is negative, Python will raise a TypeError or ValueError.

Examples:

- "cat".ljust(6) results in "cat ".

- "cat".ljust(6, '-') results in "cat---".

- "abcdefgh".ljust(5) remains "abcdefgh" because the width is not larger than the string length.

- "hi".ljust(3, '*') results in "hi*".

Related methods include rjust, center, and zfill, which align text to the right, center it, or pad with zeros, respectively. ljust is commonly used for formatting textual data into columns in console output.