How to adjust the time in the bar chart using python? - jupyter-notebook

Question

The following is my data, of which I would like to plot the monthly frequency. There are missing values.
YEAR MONTH
1960 5
1961 7
1961 8
1961 11
1962 5
1963 6
1964
1965 7
1966 7
1966 7
1966 10
1967 4
1967 8
1968
1969
1970 8
1971 6
1971 9
1971 10
1972 7
1973 6
1973 9
1974 10
1974 10
1975 10
1976
1977
1978 9
1979 11
1980 7
1980 7
1980 8
1981
1982 10
1982 12
1983
1984 7
1985 9
1986
1987
1988 9
1988 10
1989 7
1989 10
1990
1991 7
1992
1993 6
1993 7
1993 9
1993 9
1994
1995 7
1996 8
1996 9
1997 5
1998 8
1998 9
1998 10
1999 8
1999 9
2000 9
2001
2002 1
2003 5
2003 7
2003 8
2003 9
2003 10
2004
2005 11
2006 7
2006 10
2007 9
2007 11
2007 11
2008 5
2009 5
2009 7
2009 9
2009 9
2010 10
2011 5
2011 9
2011 9
2012 8
2013 7
2014 9
2015 7
2016
2017 8
2018 10
2019 11
2020
I used the following code in a Jupyter Notebook. There are other columns but I selected only the month.
#Plot Frequency
ISA = pd.read_csv (r'G\:data.csv', encoding="ISO-8859-1")
ISA = pd.DataFrame(ISA,columns=['YEAR','MONTH','TYPE'])
ISA= ISA[ISA['YEAR'].between(1960,2020, inclusive="both")]
ISA['YEAR'] = pd.to_datetime(ISA['MONTH'])
ISA = ISA.set_index('YEAR')
ISA=ISA.drop(['MSW','TC NAME', 'KNOTS','PAR BEG', 'PAR END'],axis=1)
ISA=ISA.dropna(axis=0, how='any', thresh=None, subset=None, inplace=False)
ax=ISA.groupby([ISA.index.month, 'MONTH']).count().plot(kind='bar',color='lightgray',width=1, edgecolor='darkgray')
plt.xlabel('Month', color='black', fontsize=14, weight='bold')
plt.ylabel('Monthly frequency' , color='black', fontsize=14, weight='bold',)
plt.xticks([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct','Nov','Dec'],rotation=0, fontsize=12)
ax.yaxis.set_major_formatter(FormatStrFormatter('%.0f'))
plt.yticks(fontsize=12)
plt.ylim(0,20)
plt.suptitle("Monthly Frequency",fontweight='bold',y=0.95,x=0.53)
plt.title("ISA", pad=0)
L=plt.legend()
L.get_texts()[0].set_text('Frequency')
plt.bar_label(ax.containers[0], label_type='center', fontsize=11)
plt.plot()
plt.tight_layout()
plt.show()
Using this code, the resulting plot includes February and other months. It should be zero. Can you help me adjust the bar chart? OR if there is something wrong with my code.

Answer 1

This comes close with your supplied example data:
# Read the initial data to a dataframe
import pandas as pd
from matplotlib import pyplot as plt
import matplotlib.ticker as mtick
ISA = pd.read_csv (r'data.txt', delim_whitespace=True)
ISA = pd.DataFrame(ISA,columns=['YEAR','MONTH'])
ISA['MONTH'] = ISA['MONTH'].astype(dtype='Int64')
ISA= ISA[ISA['YEAR'].between(1960,2020, inclusive="both")]
# Use `value_counts()` with that dataframe to collect counts fixing for the month numbers that are missing
# because no values ever reported for those months in imported data
months_count_collected = {}
for x in range (1,13):
if x in ISA['MONTH'].value_counts():
months_count_collected[x] = ISA['MONTH'].value_counts()[x]
#print(ISA['MONTH'].value_counts()[x])
else:
months_count_collected[x] = 0
#print(0)
# Make a dataframe with the frequency from `months_count_collected` where those with zero counts added back in
df = pd.DataFrame.from_dict(months_count_collected, orient='index', columns = ["Frequency"])
# Make plot from frequency dataframe
ax = df.sort_index().plot(kind='bar',color='lightgray',width=1, edgecolor='darkgray'); # note that `sort_index().` isn't
# needed here but would come in handy perhaps if values for unrepresented months added later/differently and can be useful when developing
# and left in so it's handy; `sort_index()` usee based on https://stackoverflow.com/a/57876952/8508004 .
# Set tick labels to the month names based on https://stackoverflow.com/a/30280076/8508004
ax.set_xticklabels(['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct','Nov','Dec'],rotation=0, fontsize=12);
ax.set_xlabel('Month', color='black', fontsize=14, weight='bold')
ax.set_ylabel('Annual frequency' , color='black', fontsize=14, weight='bold',)
#ax.set_title("Passage Frequency", pad=0);
#plt.yaxis.set_major_formatter(FormatStrFormatter('%.0f'))
ax.yaxis.set_major_formatter(mtick.FormatStrFormatter('%.0f')) # based on OP code and https://stackoverflow.com/a/36319915/8508004 to import and use `mtick` with Pandas
plt.yticks(fontsize=12)
ax.set_ylim(0,20)
plt.suptitle("Monthly Frequency",fontweight='bold',y=0.95,x=0.53)
plt.title("ISA", pad=0)
L=plt.legend()
L.get_texts()[0].set_text('Frequency')
plt.bar_label(ax.containers[0], label_type='center', fontsize=11)
plt.plot()
plt.tight_layout()
plt.show();
There's probably a more clever way to fill in the months unrepresented in the input.
And titles and labels get generated but may not be correct text right now.
What it makes: