# Log Parts

A logr log is composed of three parts:

#### Log Header

The log header provides an introduction to your log. The header block contains the path of the log file, the working directory, the name of the user, a date-time stamp, and other useful information concerning the operating environment.

#### Log Body

The log body comprises the primary content of your log. The body will be populated with print-outs from the objects you send to the log with `log_print()`, `put()` and `sep()`. The objects will be printed to the log just as they are printed to the console.

Optional notes will be written to the log for every call to `log_print()` or `put()`. The notes will follow the printing of the object, and will include a date-time stamp and the elapsed time since the last call. If the object is of class `data.frame` the number of rows and columns will also be noted.

Notes can be turned off with the `show_notes` parameter on `log_open()`, or by setting the global option `logr.notes` to FALSE.

#### Log Footer

The log footer concludes the log with another date-time stamp for the log end time, and a total elapsed time for the entire script.

Note that during batch runs or when sourcing a script, the log footer may not be generated if the script errors. Instead, the last line of the log will be the error message.

#### Example

Here is an example log showing each of the log parts described above:

    =========================================================================
    Log Path: C:/Users/dbosa/AppData/Local/Temp/RtmpQtOzhy/log/test.log
    Working Directory: C:/packages/logr
    User Name: dbosak
    R Version: R Under development (unstable) (2020-06-29 r78751)
    Machine: BOSAK-MAIN x86-64
    Operating System: Windows 10 x64 build 18362
    Base Packages: stats graphics grDevices utils datasets methods base
    Other Packages: logr_1.2.7 dplyr_1.0.7
    Log Start Time: 2020-06-30 07:15:52
    =========================================================================

    High Mileage Cars Subset

    NOTE: Log Print Time:  2020-06-30 07:15:52
    NOTE: Elapsed Time in seconds: 0.0219531059265137

                    mpg cyl  disp  hp drat    wt  qsec vs am gear carb
    Mazda RX4      21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
    Mazda RX4 Wag  21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
    Datsun 710     22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
    Hornet 4 Drive 21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
    Merc 240D      24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
    Merc 230       22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
    Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
    Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
    Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
    Toyota Corona  21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
    Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
    Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
    Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
    Volvo 142E     21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

    NOTE: Data frame has 14 rows and 11 columns.

    NOTE: Log Print Time:  2020-06-30 07:15:52
    NOTE: Elapsed Time in seconds: 0.0508558750152588

    =========================================================================
    Log End Time: 2020-06-30 07:15:53
    Log Elapsed Time: 0 00:00:00
    =========================================================================

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