Pandas - help changing values

how can I change to Females and Males instead of all of the numbers?

array([‘F’, ‘F.1’, ‘M’, ‘M.1’, ‘F.2’, ‘F.3’, ‘F.4’, ‘M.2’, ‘F.5’, ‘M.3’,
‘F.6’, ‘M.4’, ‘F.7’, ‘M.5’, ‘F.8’, ‘F.9’, ‘F.10’, ‘M.6’, ‘M.7’,
‘M.8’, ‘M.9’, ‘M.10’, ‘F.11’, ‘M.11’, ‘Unnamed: 25’, ‘Unnamed: 26’,
‘M.12’, ‘M.13’, ‘M.14’, ‘M.15’, ‘F.12’, ‘M.16’, ‘M.17’, ‘M.18’,
‘M.19’, ‘M.20’, ‘F.13’, ‘M.21’, ‘M.22’, ‘F.14’, ‘M.23’, ‘M.24’,
‘M.25’, ‘F.15’, ‘F.16’, ‘F.17’, ‘M.26’, ‘M.27’, ‘M.28’, ‘F.18’,
‘M.29’, ‘F.19’, ‘M.30’, ‘F.20’, ‘F.21’, ‘M.31’, ‘M.32’, ‘F.22’,
‘M.33’, ‘M.34’, ‘M.35’, ‘M.36’, ‘M.37’, ‘F.23’, ‘M.38’, ‘M.39’,
‘F.24’, ‘M.40’, ‘M.41’, ‘F.25’, ‘M.42’, ‘F.26’, ‘F.27’, ‘M.43’,
‘M.44’, ‘M.45’, ‘M.46’, ‘F.28’, ‘M.47’, ‘M.48’, ‘F.29’, ‘M.49’,
‘M.50’, ‘M.51’, ‘F.30’, ‘M.52’, ‘M.53’, ‘F.31’, ‘M.54’, ‘M.55’,
‘F.32’, ‘M.56’, ‘M.57’, ‘F.33’, ‘M.58’, ‘M.59’, ‘F.34’, ‘M.60’,
‘M.61’, ‘F.35’, ‘F.36’, ‘F.37’, ‘M.62’, ‘F.38’, ‘F.39’, ‘M.63’,
‘M.64’, ‘M.65’, ‘M.66’, ‘M.67’, ‘M.68’, ‘M.69’, ‘F.40’, ‘M.70’],

if df[‘Sex’].str.startswith(‘F’):

ValueError Traceback (most recent call last)
----> 1 if df[‘Sex’].str.startswith(‘F’):
2 df[‘Sex’]==“Female”

~\anaconda3\lib\site-packages\pandas\core\ in nonzero(self)
1325 def nonzero(self):
-> 1326 raise ValueError(
1327 f"The truth value of a {type(self).name} is ambiguous. "
1328 “Use a.empty, a.bool(), a.item(), a.any() or a.all().”

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

Note that == (double equals) is to compare values and = (single equal) is to assign values. Maybe you should replace the == with =. Try it and let me know.