Tag: Python
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Convert Unix timestamps to datetime in Pandas with pd.to_datetime
Want to convert an integer Python Pandas column from Unix time to datetime? Use pd.to_datetime, passing the int column and the “unit” keyword argument, set to “s” (seconds): If the column is in ms, then say unit=’ms’
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Pandas to_period: Comparing dates by month, quarter, or year
Want to check if two Python Pandas datetimes are in the same month/quarter/year? Convert them both to periods, and compare with ==:
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Pandas to_period: Finding which period contains a datetime
Want to find which time period contains a Python Pandas datetime? Use to_period: This returns a Pandas “Period” object, useful (among other things) for checking if two dates are within the same period.
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Find leap years in a Pandas datetime series with dt.is_leap_year
Want to find leap years in a Python Pandas datetime series? Use dt.is_leap_year:
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Pandas dt.is_month_start: Checking period boundaries in a series
Want to know if values in a Python Pandas datetime series are at the start/end of a period? Get a boolean series from:
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`★ Insight ─────────────────────────────────────`
Use dt.day_of_week to get the day number from a Python Pandas datetime series. But is 0 Sunday or Monday? Or not used at all? Better: Use the day_name method: Good news: It returns a series of strings!Bad news: It’s 4x slower.
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Pandas .dt accessor: Extracting year, hour, and day_of_week
Want to grab a part of datetime value in a Python Pandas data frame column? Use “dt”: day_of_week returns an integer, where 0 is Monday and 6 is Sunday.
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pandas read_csv date parsing: Using the date_format keyword
Reading a CSV into Python Pandas, and parse_dates doesn’t recognize the format? Pass the date_format keyword arg: All strftime codes work!
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Pandas parse_dates: Reading CSV date columns as datetimes
Reading a CSV into Python Pandas, and want a column to be treated as datetime values? Use parse_dates: Bonus: The PyArrow engine often (not always) parses columns that look like dates.
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pd.to_datetime: Converting a pandas string column to datetimes
Want to take a Python Pandas series of strings, and get datetime values? Use pd.to_datetime: Notice: It’s not a method! It’s a top-level pd function. Specify a non-standard “format” with a strftime string: