Question

我有一个包含不同数据格式的.csv文件，我正在尝试使用同一列上的值进行操作。

我的csv文件是这样的：

ExpandoObject

示例：

DictionaryValueProvider

如果它们的差值大于x，我想在第二列中减去值。（只有那些，我不关心其他人）。

到目前为止我的代码：

"int","float","stirng", more data

输出如下：

"2","1.378","Johnny"
"1","1.379","Walker"
"5","1.380","Jack"
"8","1.700","Daniels"
"8","1.710","Baileys"
"8","1.381","Monkey"
"8","1.711","Shoulder"
"8","1.383","Captain"
"8","1.385","Morgan"
"8","1.392","Drinks"
More rows

但我希望如此：

with open ('input.csv', 'r') as file, open ('output.csv', 'w') as f_out:
    readCSV = csv.reader(file)
    writeCSV = csv.writer(f_out, lineterminator='\n')
    last = None

    for row in readCSV:
        datalat = float(row[1])

        if last is not None:
            #print("difference -> %f" %(datalat-last))
            outp = (datalat-last)
            if outp <= 0.02:
                writeCSV.writerow(row)
            last = datalat

所以它应该做的只是写行差异小于0.02的行，如果有一个有较大差异的行丢弃它，则将下一行与最后写入的行进行比较，而不是最后一次丢弃的行。

Answer 1

两件事：

您应该采用差异的绝对值（使用abs），因为您不知道apriori中哪一个更大。
如果条件已满足，则仅更新last，因此last永远不会被废弃。

last = float(next(readCSV)[1])  # assign first reference value
f_out.seek(0)                   # return to start of file
for row in readCSV:
    datalat = float(row[1])
    diff = abs(datalat-last)
    if diff <= 0.02:
        writeCSV.writerow(row)
        last = datalat

过滤csv中的特定行，跟踪最后一个值

1 个答案: