For loop iteration missing values out?-CodePudding

I'm currently trying to create a column in a pandas dataframe, that creates a counter that equals the number of rows in the dataframe, divided by 2. Here is my code so far:

# Fill the cycles column with however many rows exist / 2
for x in ((jac_output.index)/2):
    jac_output.loc[x, 'Cycles'] = x 1

However, I've noticed that it misses out values every so often, like this:

[ Missing Values1

Why would my counter miss a value every so often as it gets higher? And is there another way of optimizing this, as it seems to be quite slow?

CodePudding user response：

you may have removed some data from the dataframe, so some indicies are missing, therefore you should use reset_index to renumber them, or you can just use

for x in np.arange(0,len(jac_output.index),1)/2:.

CodePudding user response：

You can view jac_output.index as a list like [0, 1, 2, ...]. When you divide it by 2, it results in [0, 0.5, 1, ...]. 0.5 is surely not in your original index.

To slice the index into half, you can try:

jac_output.index[:len(jac_output.index)//2]