Assign values to Pandas columns based on another column iteratively

I have a variable in Pandas dataframe called "label" which contains multiple string values (for example: 'label1', "label2', 'label3'...).

label
label1
label1
label23
label3
label11

I output all unique values into a list and then create new variables

unique_labels = df['label'].unique()

for i in unique_labels: # create new single label variable holders
    df[str(i)] = 0

Now I have

label    label1    label2 .... label23
label1     0         0            0
label23    0         0            0

I want to assign corresponding value based on 'label' onto the new single label variables, as following

label    label1    label2 .... label23
label1     1         0            0
label23    0         0            1

Here is my code

def single_label(df):
for i in range(len(unique_labels)):
    if df['label'] == str(unique_labels[i]):
        df[unique_labels[i]] == 1


df = df.applymap(single_label)

Getting this error

TypeError: ("'int' object is not subscriptable", 'occurred at index Unnamed: 0')