Python 浮动替换多个

Question

I will straight to the point.

First I have an exam scores like this: ( The scores as string )

1. Student A: "550.4" -> "." = point
2. Student B: "1,098.9" -> ","(coma) = thousand symbol, "." = point
3. Student C: "1,100.00" -> ","(coma) = thousand symbol, "." = point
4. Student D: "999.99" -> "." = point

Criteria:

1. When a score equal to or less than 600.00, then display "Study more!"
2. score <= 600, display "Study more!"
3. When a score equal to or more than 1,000.00 (thousand), then display "Get your reward!"
4. score => 1,000.00, display "Get your reward!"

What I want is when one of the students score's meet one of the criteria then display a special messages. So to compare the scores with criteria I use this code ( code below ):

'''
SA = "550.40"
SB = "1,098.90"
SC = "1,100.00"
SD = "999.99"

SA = float(SA) #return 550.4 (as number)
SB = float((SB[0:8]).replace(',','.')) #return error : 'ValueError: could not convert string to float: 1,098.90'
SC = float((SC[0:8]).replace(',','.')) #return error : 'ValueError: could not convert string to float: 1,100.00'
SD - float(SD) #return 999.99 (as number)
'''

Note: I use [0:8] in hope all the score value (as string) will be convert to score(as number, float) If [0:8] does not get all the score value then please correct me

Whenerver I use "replace(',','.')" and meet this condition "XX,XXX.XX" (XX-coma-XXX-point-XX) I will get those Error, and I don't know why.

Please help me. Thank you.

Answer 1

Your replacement results in a string with multiple periods: you can only have one (decimal) period. You would need to replace the comma with nothing (empty string), or possibly an underscore (for readability, but that doesn't matter here, since the intermediate result isn't shown):

SB = "1,098.90"
SC = "1,100.00"

SB = float(SB[:8].replace(',', ''))
SC = float(SC[:8].replace(',', ''))

Answer 2

You should replace it with empty string instead of ".". You also do not need to slice SB and SC .

SB = "1,098.90"
SC = "1,100.00"

SB = float(SB.replace(',',''))
SC = float(SC.replace(',',''))