For Loops

For Loop in C:

char *my_string = "Python";
for (int i = 0; i < strlen(my_string); i++) {
    printf(%c\n", my_string[i]);
}

Python in C Style:

my_string = "Python"
for i in range(len(my_string)):
    print(my_string[i])

While the Python one certainly is shorter and looks cleaner... it's still not Pythonic. It's ugly and not the most readable code.

For Loop... Python Style

my_string = "Python"
for letter in my_string:
    print letter

So easy, a caveman can do it! But, how does this happen under the hood?

Remember Data Types chapter? Strings are iterable just like in C. The "in" operator simply calculates the count of my_string and iterates through it as var letter. The value of letter is my_string[i].

For Looping Dictionaries

for key, value in dict.iteritems():
    pass

x = {'stu1':'James', 'stu2':'Bob', 'stu3':'Rengar'}

for stu_id, name in x.iteritems():
    print "{}'s name is {}".format(stu_id, name)