如何解析含超长格式时间戳的日志并转换为1970-01-01以来的毫秒数？

Hey there! That long timestamp you're working with (636597250599883050, 636597142599883050) is .NET DateTime Ticks—a format that counts 100-nanosecond intervals starting from January 1, 0001 (UTC). Here's a straightforward way to convert it to milliseconds since the Unix epoch (January 1, 1970):

Step-by-Step Explanation #

1. Use the fixed epoch offset: The number of ticks between the .NET epoch (0001-01-01 UTC) and the Unix epoch (1970-01-01 UTC) is a constant: 621355968000000000.
2. Calculate ticks since Unix epoch: Subtract this fixed offset from your target tick value.
3. Convert to milliseconds: Since 1 tick = 100 nanoseconds, divide the result by 10000 (because 1 millisecond = 1,000,000 nanoseconds = 10,000 ticks).

Example Code (Python) #

def ticks_to_unix_ms(ticks):
    # Fixed ticks between .NET epoch (0001-01-01) and Unix epoch (1970-01-01)
    net_to_unix_ticks = 621355968000000000
    # Convert to milliseconds since Unix epoch
    return (ticks - net_to_unix_ticks) // 10000

# Test with your sample timestamps
local_time_ticks = 636597250599883050
utc_time_ticks = 636597142599883050

print(ticks_to_unix_ms(local_time_ticks))  # Output: 1525197459988
print(ticks_to_unix_ms(utc_time_ticks))    # Output: 1525194379988

Verify the Result #

If you take the UTC result (1525194379988) and convert it back to a human-readable time:

import time
print(time.gmtime(1525194379988 / 1000))

You'll get:

time.struct_time(tm_year=2018, tm_mon=5, tm_mday=1, tm_hour=17, tm_min=6, tm_sec=19, tm_wday=1, tm_yday=121, tm_isdst=0)

Which aligns perfectly with the Unix timestamp example you provided!

内容的提问来源于stack exchange，提问作者sergeyvin