Question

我想将字符串中的数字和运算符分开，怎么办？

我正在使用拆分并获取数字，但无法获取运算符该代码仅在运算符为'+'时有效，否则会出错！

T = "123+456"
op = '+' or '-'
for i in range(T):
    n = input()
    n1,n2 =  n.split(op)
    print(n1)
    print(n2)

Answer 1

您可以使用正则表达式通过r'(\d+)|([+\-\*/])'查找字符串中存在的数字和运算符，它们匹配一个或多个数字，或者匹配+,-,*,\之外的运算符

import re

def get_num_op(s):

    #Get all matches
    matches = re.findall(r'(\d+)|([+\-\*/])', s)
    #[('123', ''), ('', '+'), ('456', ''), ('', '*'), ('7', ''), ('', '*'), ('8', '')]

    #Remove empty matches from the list
    matches = [item for t in matches for item in t if item]

    return matches

print(get_num_op("123+456"))
print(get_num_op("123+45*6/7"))

输出将为

['123', '+', '456']
['123', '+', '45', '*', '6', '/', '7']

Answer 2

您可以使用re进行拆分：

import re

T = "123+456"
re.split('((\w)[0-9]*)', T)

out:['', '123', '+', '456', '']

Answer 3

此代码可与"+","-","*","/"这组运算符配合使用。它将为您提供operand1，operand2和operator。

user_input="12-23"
operator_list = ["+","-","*","/"]

input_list = [x for x in user_input]

for operator in operator_list:
    if operator in input_list:
        index = input_list.index(operator)
        break

operand1 = user_input[:index]
operand2 = user_input[index+1:]
print(operand1 , operator, operand2)

输出

12 - 23

在保留操作员的同时从操作员拆分

3 个答案: