Welcome!
Agree with all the comments. It's generally best practice to find a way to accomplish what you want in Pandas/Numpy without iterating over rows/columns.
If the objective is to "find rows where any column contains the value 'x'), life is a lot easier than you think.
Below is some data:
import pandas as pd
df = pd.DataFrame({
'a': range(10),
'b': ['x', 'b', 'c', 'd', 'x', 'f', 'g', 'h', 'i', 'x'],
'c': [False, False, True, True, True, False, False, True, True, True],
'd': [1, 'x', 3, 4, 5, 6, 7, 8, 'x', 10]
})
print(df)
a b c d
0 0 x False 1
1 1 b False x
2 2 c True 3
3 3 d True 4
4 4 x True 5
5 5 f False 6
6 6 g False 7
7 7 h True 8
8 8 i True x
9 9 x True 10
So clearly rows 0, 1, 4, 8 and 9 should be included.
If we just do df == 'x', pandas broadcasts the comparison across the whole dataframe:
df == 'x'
a b c d
0 False True False False
1 False False False True
2 False False False False
3 False False False False
4 False True False False
5 False False False False
6 False False False False
7 False False False False
8 False False False True
9 False True False False
But pandas also has the handy .any method, to check for True in any dimension. So if we want to check across all columns, we want dimension 1:
rows = (df == 'x').any(axis=1)
print(rows)
0 True
1 True
2 False
3 False
4 True
5 False
6 False
7 False
8 True
9 True
Note that if you want your solution to be truly case sensitive like what you're using with the .str method, you might need something more like:
rows = (df.applymap(lambda x: str(x).lower() == 'x')).any(axis=1)
The correct rows are flagged without any looping. And you get a series back that can be used for indexing the original dataframe:
df.loc[rows]
a b c d
0 0 x False 1
1 1 b False x
4 4 x True 5
8 8 i True x
9 9 x True 10
rows = np.where(df.values == 'x')[0]. Don't iterate through dataframes if you can help it.