Drop ALL rows in pandas until a specific string is found then stop dropping-CodePudding

I have a dataframe and I want to delete every row until a specific string is found.

I have tried a couple things but nothing seems to be working. Here is what I have tried:

df[((df.Plate != 'Group Summaries'))]
df.loc[: df[(df['Plate:'] == 'Group Summaries')].index[0], :]
df[(df['Plate:'] == "Group Summaries").idxmax():]

CodePudding user response：

Why don't you find the first index where this case appears and then delete all previous row?

import pandas as pd

# Data
df = pd.DataFrame(
    {"Plate": ["a", "b", "a", "c", "a", "c", "c"]})

# First index where values is c
idx = df.index[df["Plate"].eq("c")].min()

# Drop previous rows
df = df[idx:]

CodePudding user response：

You can use:

df[df['Plate'].eq('Group Summaries').cummax()]

How it works:

mark True the rows with "Group Summaries" in the "Plate" column
forward the True to all next rows with cummax
use boolean indexing to select the rows