Question

我有一个数据框（DF）我需要遍历每一行，并检查该行是否满足某些条件如果它们然后标记了该行（例如，我添加了另一列标记为“ flag”的列并将其等于1），则在同一循环中检查是否存在其他具有类似条件的行，如果存在，则也对其进行标记。在下一个循环中，查看相同的DF，但排除标记的行。 DF的大小将从NxM变为（N-n）x M，其中n是标记的行数。循环将继续进行，直到len（DF）<= 1（意味着直到所有行都标记为1）为止。 for循环不起作用，因为随着循环的进行，DF的大小会缩小，因此我只能使用带有增量的while循环。但是，如何设置增量（它应该是动态的）？

我真的不确定如何解决这个问题。

这是失败的尝试。

a=len(DF.loc[DF['flag'] != 1]) #should be  (NxM) initially
i = 0
# at every loop we redefine size of DF in variable a
while a >= 1:
        print(i)
        # select first row          
        row = DF.loc[DF['flag'] != 1].iloc[[i]]
        # flag row if conditions are met
        DF['flag'].values[i] = np.where(if conditions met, 1, '')

        #there is another piece of code that looks for rows with similar 
        #conditions but won't add it here

        # the following variable a redefines length of DF 
        a=len(allHoldingsLookUp.loc[allHoldingsLookUp['flag'] != 1])
        i+=1

我在这里有问题。增量我不工作。说“ i”达到100，而DF的长度缩小到70，则代码失败。需要以不同的方式设置增长，但不确定如何。任何意见或建议都将受到欢迎。

Answer 1

如果此更改有效，请尝试。.

a=len(DF.loc[DF['flag'] != 1]) #should be  (NxM) initially
# at every loop we redefine size of DF in variable a
while a >= 1:
        i = 1
        # select first row          
        row = DF.loc[DF['flag'] != 1].iloc[[i]]
        # flag row if conditions are met
        DF['flag'].values[i] = np.where(if conditions met, 1, '')

        #there is another piece of code that looks for rows with similar 
        #conditions but won't add it here

        # the following variable a redefines length of DF
        try:
            a=len(DF.loc[DF['flag'] != 1])
        except:
            break

Answer 2

可以请您尝试一下。希望它能工作。

def recur(DF):
  row = DF.loc[DF['flag'] != 1].iloc[[1]]            
  DF['flag'].values[1] = np.where(if conditions met, 1, '')
  #there is another piece of code that looks for rows with similar 
  #conditions but won't add it here 
  # the following variable a redefines length of DF 
  a=len(DF.loc[DF['flag'] != 1])
  if a >= 1:
    recur(DF.loc[DF['flag'] != 1])
  return none

如何在while循环中正确设置增量？

2 个答案: