check if value belong to a dataframe code example

Example 1: pandas check if any of the values in one column exist in another

df["exists"] = df.drop("target", 1).isin(df["target"]).any(1)
print(df)

    target  A       B       C       exists
0   cat     bridge  cat     brush   True
1   brush   dog     cat     shoe    False
2   bridge  cat     shoe    bridge  True

Example 2: pandas look for values in column with condition

df.loc[(df['column_name'] >= A) & (df['column_name'] <= B)]