#named indexes:

txt1 = "My name is {fname}, I'm {age}".format(fname = "John", age = 36)

#numbered indexes:

txt2 = "My name is {0}, I'm {1}".format("John",36)

#empty placeholders:

txt3 = "My name is {}, I'm {}".format("John",36)

​

print(txt1)

print(txt2)

print(txt3)

​