如何删除列表中项目中的字符（Python）

Question

I'm learning python and I've made a quick grade calculator that checks if the first letter is D for daily grade, or M for major grade (Major is weighed differently than daily). However I need to actually remove the D and M once I move it to their respective lists. How would I go about doing this? Do me a favor and keep it simple :D.

grades = ['D 85', 'D 100', 'M 20', 'D 70']

I have code that puts the Daily grades in the proper list and vice versa for major.

Daily = ['D 85', 'D 100', 'D 70']
Major = ['M 20']

Now I need to remove the D and the M from each item in the list. daily.replace didn't work and I tried a

for i in list: 
   for c in i:
      newdaily.replace('D',"")

And same for the major list. How would I go about this?

Answer 1

It seems like really you want to be splitting the string and taking the second of the two parts. If you take a single string you can do so with

'D 85'.split()[1] # "85"

To do this to the whole list:

grades = ['D 85', 'D 100', 'M 20', 'D 70']
numeric_grades = [g.split()[1] for g in grades]

Know that there is nothing in the above to convert the strings to int s, but that can be easily added

numeric_grades = [int(g.split()[1]) for g in grades]

Answer 2

It's not so matter of a replacement, as a string cut. From what I understand, you want cut first character or two?

grade = "D 85"
grade[2:]
> "85"

String is an array, and you can ask for some part of it. [2:] means since third (we count from 0) character to end.

EDIT: To process all grades and remove first character and store result in new list ( gradesClean ):

grades = ["D85", "D100", "M20", "D70"]
gradesClean = []
for g in grades:
    gradesClean.append(g[1:])

gradesClean
> ['85', '100', '20', '70']

Answer 3

You could try something like this.

raw_grades = ["D 85", "D 100", "M 20", "D 70"]
chars_to_replace = ["D", "M"]

sanitized_grades = []

for i in raw_grades:
    for char in chars_to_replace:
        i = i.replace(char,"")

    sanitized_grades.append(i.strip())

print(sanitized_grades) # ['85', '100', '20', '70']

Hope this helps.

Answer 4

In-buit strip() function would also work here, with list-comprehension.

>>> grades = ["D 85", "D 100", "M 20", "D 70"]
>>> grades_num = [ele.strip('D ').strip('M ') for ele in raw_grades]
['85', '100', '20', '70']  # output

Answer 5

You can use remove Example:

list=['A','B','C']

list.remove('A')