从字符串中删除特定不需要的字符的迭代循环

Question

我想在数据框中获取字符串“APPLES_10_4”并将其变为“APPLES”。我想出的代码如下：

import pandas as pd
data = ['APPLES_10_4']

Name_Parameters = []
df = pd.DataFrame(data, columns = ['fruit'], index = ['count'])

    
def badletters(lastletter):
    badletters = ["1","2","3","4","5","6","7","8","9","_"]
    if lastletter in badletters:
        return True
    else:
        return False   

def stripe(variable):
    tempStrippedVariable = variable
    foundEndVariable = False
    while not foundEndVariable:
        lastletter = tempStrippedVariable [:-1]
        if badletters(lastletter):
            tempStrippedVariable = tempStrippedVariable [:-1]
        else:
            foundEndVariable = True
    strippedVariable = tempStrippedVariable
    return strippedVariable

for variable in df:
strippedVariable = stripe(str(variable))
prefixes = []
if strippedVariable not in prefixes:
    prefixes.append(strippedVariable)
print(df)

我得到的输出是带有 ['APPLES_10_4'] 的原始数据框，而不是显示 ['APPLES'] 的更改后的数据框。

Answer 1

一些数据框元素是整数，而不是字符串。您可以在调用stripe()之前将它们转换为字符串

for variable in df:
    strippedVariable = stripe(str(variable))
    if strippedVariable not in prefixes:
        prefixes.append(strippedVariable)
print(prefixes)

或者你可以跳过它们。

for variable in df:
    if not isinstance(variable, str):
        continue
    strippedVariable = stripe(variable)
    if strippedVariable not in prefixes:
        prefixes.append(strippedVariable)
print(prefixes)

另一个错误在stripe():

lastletter = tempStrippedVariable [:-1]

应该是

lastletter = tempStrippedVariable [-1]

您将lastletter 设置为整个字符串除了最后一个字母。

但是整个函数可以简单地替换为：

def stripe(variable):
    badletters = ["1","2","3","4","5","6","7","8","9","_"]
    return variable.rstrip(badletters)

最后，for variable in df 不会遍历数据框内容，只是遍历列名。见How to iterate over rows in a DataFrame in Pandas

for row in df.itertuples():
    variable = row[0]
    strippedVariable = stripe(variable)
    if strippedVariable not in prefixes:
        prefixes.append(strippedVariable)