Question

我的名单是['1','2','to','3']

我需要写一个逻辑

将字符串中的“ 1”“ 2”转换为整数1、2。
打印错误消息，因为其中包含'to'字符串并且无法将其转换为整数

这是我现在拥有的代码：

def average_file(filename):

    inputFile = open(filename, "r")
    inList = []
    results = []
    n = []

    for line in inputFile:
        inList.append(line.strip())  #inList.append(line)
        n = [int(elem) for elem in inList if elem.isdigit()] #I only remove the string and leave integer in my list, but I need a check logic to print error msg
        results = list(map(int, n))
    inputFile.close()

    results = sum(results)/len(results)
    return results

Answer 1

将字符串的'1''2'转换为1，2是整数打印由于包含“ to”字符串，因此无法将其转换为错误消息整数

source = ['1', '2', 'to', '3']
result = []

for item in source:
    try:
        result.append(int(item))
    except ValueError as ex:
        print('Not integer: {}'.format(item))

print(result)

Answer 2

几件事：

执行此操作的pythonic方法是期望它是一个全数字值，如果不是，则处理错误。
您可以使用with处理文件的生存期。
您可以在读取过程中计算元素的总和和计数，而无需保存其他数组（因此知道平均值）。

strip

int

int(variable)是多余的：

去那里：

def average_file(filename):

    summary = 0
    count = 0

    with open(filename, "r") as inputFile:
        for line in inputFile:
            try:
                summary += int(line)
                count += 1
            except ValueError as e:
                print('Can not parse "{0}" to a number'.format(line))

                # If reached here one of the values in the file is not a number and None is returned immediately
                return None

    # If count is 0 return None, otherwise return the average
    return (summary / count) if count else None

答案经过OP的一些澄清后被编辑：
如果其中一个值不是数字，请立即返回None。

Answer 3

尝试将每个项目转换为结果列表。如果转换失败，则输出错误消息。

l = ['1','2','to','3']

result = []
for item in l:
    try:
        result.append(int(item))
    except ValueError:
        print(item)

Answer 4

您可以使用render (){ return ( <Doughnut data={this.state.chartData} options={{ padding:"0px", responsive:false, maintainAspectRatio:false, defaultFontSize:"14px", width:"400", height:"400", legend:{ display:false, }, plugins:{ datalabels: { color:'#000000', anchor: "start", align:"end", formatter: function(value, context) { return context.chart.data.labels[context.dataIndex]; } } } }} /> ) } / try块将有效的整数文字与其他所有内容分开：

except

对于您而言，您可以只在candidates = ['1','2','to','3'] for candidate in candidates: try: # attempt the conversion value = int(candidate) except ValueError: # conversion failed! print(candidate, 'is not an integer') else: # conversion succeeded print(candidate, 'is the integer', value)子句中收集值：

else

Answer 5

l = ['1', '2', 'word', '4']

您可以这样做：

n = [int(i) if i.isdigit() else print('\nNot able to convert: '+i) for i in l]

输出：

Not able to convert: word
l = [1, 2, None, 4]

如何检查列表中的整数和字符串

5 个答案: