Question about IF ELSE and mathematic in python-CodePudding

Data Time,PM2.5, 1/1/2014,9 2/1/2014,10

import pandas as pd

df = pd.read_csv('xx.csv')
data = pd.DataFrame(df)

def calculation(y):
    if 0 < y and y < 12:
        bello=data.assign(API=(50/12)*y)
    elif 12.1 <= y and y <= 50.4:
        bello=data.assign(API=(((100-51)/(50.4-12.1))*(y-12.1)) 51)
    elif 50.5 <= y and y <= 55.4:
        bello=data.assign(API=(((150-101)/(55.4-50.5))*(y-50.5)) 101)
    elif 55.5 <= y and y <= 150.4:
        bello=data.assign(API=(((200-151)/(150.4-55.5))*(y-55.5)) 151)
    elif 150.5 <= y and y <= 250.4:
        bello=data.assign(API=(((300-201)/(250.4-150.5))*(y-150.5)) 201)
    elif 250.5 <= y and y <= 350.4:
        bello=data.assign(API=(((400-301)/(350.4-250.5))*(y-250.5)) 301)
    else:
        bello=data.assign(API=(((500-401)/(500.4-350.5))*(y-350.5)) 401)
    return bello

y=data['PM2.5']
print(calculation(y))

Hi everyone,

I want to convert air quality data to PM2.5 with above condition and equation using coding above.

I received an error "ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().".

I hope someone can tell me what is the problem.

Thanks in advance.

I wrote the coding above but show error. Hope someone can tell what is the problem of my coding.

CodePudding user response：

For example, you can rewrite the function for single value and use df.apply(...)

import pandas as pd
data  = pd.DataFrame({'PM2.5': [15, 50, 1000]})

def calculation(y):
    if 0<y<12:
        return (50/12)*y
    elif 12.1 <= y  <= 50.4:
        return (((100-51)/(50.4-12.1))*(y-12.1)) 51
    ## .... 
    else:
        return (((500-401)/(500.4-350.5))*(y-350.5)) 401

y=data['PM2.5']
print(y.apply(calculation))

This is close to your code, however faster solutions might exists by vectorizing.