Time Formatting

API Reference

D3 includes a helper module for parsing and formatting dates modeled after the venerable strptime and strftime C-library standards. These functions are also notably available in Python's time module.

# d3.time.format(specifier)

Constructs a new time formatter using the given specifier. The specifier string may contain the following directives.

• %a - abbreviated weekday name.
• %A - full weekday name.
• %b - abbreviated month name.
• %B - full month name.
• %c - date and time, as "%a %b %e %H:%M:%S %Y".
• %d - day of the month as a decimal number [01,31].
• %H - hour (24-hour clock) as a decimal number [00,23].
• %I - hour (12-hour clock) as a decimal number [01,12].
• %j - day of the year as a decimal number [001,366].
• %m - month as a decimal number [01,12].
• %M - minute as a decimal number [00,59].
• %p - either AM or PM.
• %S - second as a decimal number [00,61].
• %U - week number of the year (Sunday as the first day of the week) as a decimal number [00,53].
• %w - weekday as a decimal number [0(Sunday),6].
• %W - week number of the year (Monday as the first day of the week) as a decimal number [00,53].
• %x - date, as "%m/%d/%y".
• %X - time, as "%H:%M:%S".
• %y - year without century as a decimal number [00,99].
• %Y - year with century as a decimal number.
• %Z - time zone offset, such as "-0700".
• %% - a literal "%" character.

For %U, all days in a new year preceding the first Sunday are considered to be in week 0. For %W, all days in a new year preceding the first Monday are considered to be in week 0. In some implementations of strftime and strptime (as in Python), a directive may include an optional field width or precision; this feature is not yet implemented in D3, but may be added in the future. Also note that the JavaScript environment does not provide a standard API for accessing locale-specific date and time formatters, so D3's implementation assumes the conventions of the English language (United States).

# format(date)

…

# format.parse(string)

…

# d3.time.format.utc(specifier)

…

# d3.time.format.iso

… %Y-%m-%dT%H:%M:%SZ