Stata String Functions

Contents

  1. Stata String Functions
    1. General Syntax
      1. Date and Datetime Masks
    2. Clock
    3. Date
    4. HalfYearly
    5. Monthly
    6. Quarterly
    7. Weekly
    8. Yearly

General Syntax

Date and Datetime Masks

Date and datetime conversion functions use a concept of masks. These instruct the function how to interpret the string.

A mask of "DMY" can parse all of:

Spaces are ignored in a mask; "DMY" is equivalent to "D M Y".

The mask "DMY" cannot parse a string with a two-digit year. A two-digit prefix can be applied to "Y" in the mask, such as "DM19Y". If a string has a two-digit year, such a mask will cause the year to be interpreted as being within the 1900s. If a string has a four-digit year, the mask will not mutate the value.

Clock

Convert a string date and time into the number of milliseconds since the Stata epoch (01jan1960 00:00:00.000).

There are two functions: clock and Clock.

To create a datetime that ignores leap seconds, try: 

generate double datetime = clock(string, "YMDhms")
format datetime %tc

To create a datetime that includes leap seconds since the epoch, try: 

generate double datetime = Clock(string, "YMDhms")
format datetime %tC

As noted above, the mask should be composed of: "Y", "M", "D", "h", "m", and "s". See above for details on masks.

Date

Convert a string date into the number of days since the Stata epoch (01jan1960 00:00:00.000). 

generate long date = date(string, "MDY")
format date %td

As noted above, the mask should be composed of: "Y", "M", and "D". See above for details on masks.

HalfYearly

Convert a string date into the number of half years since the Stata epoch (01jan1960 00:00:00.000). 

generate int halfyear = halfyearly(string, "YH")
format halfyear %th

As noted above, the mask should be composed of: "Y" and "H". See above for details on masks.

Monthly

Convert a string date into the number of months since the Stata epoch (01jan1960 00:00:00.000). 

generate int month = monthly(string, "YM")
format month %tm

As noted above, the mask should be composed of: "Y" and "M". See above for details on masks.

Quarterly

Convert a string date into the number of quarters since the Stata epoch (01jan1960 00:00:00.000). 

generate int quarter = quarterly(string, "YQ")
format quarter %tq

As noted above, the mask should be composed of: "Y" and "Q". See above for details on masks.

Weekly

Convert a string date into the number of weeks since the Stata epoch (01jan1960 00:00:00.000). 

generate int week = weekly(string, "YW")
format week %tw

As noted above, the mask should be composed of: "Y" and "W". See above for details on masks.

Yearly

Convert a string date into the number of years since the Stata epoch (01jan1960 00:00:00.000). 

generate int year = yearly(string, "Y")
format year %th

As noted above, the mask should be composed of: "Y" and "W". See above for details on masks.

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