Pandas Datetime: Count year-country wise frequency of reporting dates of unidentified flying object (UFO)
Pandas Datetime: Exercise-10 with Solution
Write a Pandas program to count year-country wise frequency of reporting dates of unidentified flying object (UFO).
Sample Solution :
Python Code :
import pandas as pd
df = pd.read_csv(r'ufo.csv')
df['Date_time'] = df['Date_time'].astype('datetime64[ns]')
print("Original Dataframe:")
print(df.head())
df['Year'] = df['Date_time'].apply(lambda x: "%d" % (x.year))
result = df.groupby(['Year', 'country']).size()
print("\nCountry-year wise frequency of reporting dates of UFO:")
print(result)
Sample Output:
Original Dataframe: Date_time city ... latitude longitude 0 1949-10-10 20:30:00 san marcos ... 29.883056 -97.941111 1 1949-10-10 21:00:00 lackland afb ... 29.384210 -98.581082 2 1955-10-10 17:00:00 chester (uk/england) ... 53.200000 -2.916667 3 1956-10-10 21:00:00 edna ... 28.978333 -96.645833 4 1960-10-10 20:00:00 kaneohe ... 21.418056 -157.803611 [5 rows x 11 columns] Country-year wise frequency of reporting dates of UFO: Year country 1949 us 1 1955 gb 1 1956 us 1 1960 us 1 1961 us 1 1965 gb 1 us 1 1966 us 2 1968 us 2 1970 us 2 1971 us 1 1972 us 2 1973 us 1 1974 gb 1 us 2 1975 us 1 1976 gb 1 us 1 1977 us 2 1978 us 1 1979 us 3 1980 us 3 1984 us 3 1985 gb 1 1988 us 4 1989 us 2 1990 us 1 1991 us 2 1992 us 4 1993 us 2 1994 ca 1 us 2 1995 us 2 1996 us 3 1997 us 4 1998 ca 1 us 8 1999 us 10 2000 ca 1 us 6 2001 au 1 ca 1 us 6 2002 au 1 ca 1 us 5 2003 us 8 2004 ca 1 us 1 dtype: int64
Python Code Editor:
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Previous: Write a Pandas program to convert given datetime to timestamp.
Next: Write a Pandas program to extract unique reporting dates of unidentified flying object (UFO).
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Python: Tips of the Day
Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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