Suppose, I have a data frame like this:
Col1 Col2
1 A
5 B
3 C
2 D
Specifically in python
DF = pd.DataFrame({'Col1' : [1,5,3,2],'Col2':['A','B','C','D']})
If I plot col1 values in matplotlib with following code:
plt.plot(DF.Col1)
I get this figure
Now I want to annotate col2, where the values are greater than 2.That's mean, it annotates "B" and "C" at 5 and 3 in the figure. How can I do that?
Col1 contains the Col2 letters values, so you can read every value of col1 and check if is greather than 2. If it's so, you can take the letter at the same index in Col2.
Here is an example:
d={'Col1' : [1,5,3,2],'Col2':['A','B','C','D']}
#get the data
col1=d["Col1"]
col2=d["Col2"]
def getGreaterThanNumb(val, lett, numb):
if len(val) != len(lett):
#col1 and col2 must have the same lenght!
return
for i in range(0, len(lett)):
if val[i]>numb:
print(lett[i]) #Print or store it in a collection
getGreaterThanNumb(col1, col2, 2)
Your output will be:
ANNOTATIONS
Now, the coords of any vertices (based on the previous code) is the couple (x,y) = (i,val[i]), so you can write:
for i in range(0, len(lett)):
if val[i]>numb:
#print(lett[i]) #Print or store it in a collection
plt.annotate(lett[i], (i,val[i])) #Annotate
Here is a complete code (without using Pandas, but the behaviour is the same):
import matplotlib.pyplot as plt
d={'Col1' : [1,5,3,2],'Col2':['A','B','C','D']}
#get the data
col1=d["Col1"]
col2=d["Col2"]
coords = plt.plot(col1)
plt.ylabel('some numbers')
def getGreaterThanNumb(val, lett, numb):
if len(val) != len(lett):
#col1 and col2 must have the same lenght!
return
for i in range(0, len(lett)):
if val[i]>numb:
plt.annotate(lett[i], (i,val[i])) #Annotate
#Call the annotation method
getGreaterThanNumb(col1, col2, 2)
#plot
plt.show()
Your output will be:
Please Check this snippet .I have created another dataframe named x which holds your sorted value based on requirement.
Here to show the difference between both conditions, I created 2 line plots that overlaps based on your value. But if you just want single line then you can remove
ax.plot(x['Col1'],label='Line1')
import matplotlib.pyplot as plt
import pandas as pd
df = pd.DataFrame({'Col1' : [1,5,3,2],'Col2':['A','B','C','D']})
x=df.loc[df['Col1'] > 2]
fig, ax = plt.subplots()
ax.plot(df['Col1'],label='Line2')
ax.plot(x['Col1'],label='Line1')
for x,y,z in zip(x.index.tolist(),x['Col1'],x['Col2']):
ax.annotate(z,xy=(x,y))
plt.legend()
plt.show()
