<filename>count-letter.py
#!/usr/bin/python
import json

count = {"a": 0, "b": 0, "c": 0, "d": 0, "e": 0, "f": 0, "g": 0, "h": 0,
    "i": 0, "j": 0, "k": 0, "l": 0, "m": 0, "n": 0, "o": 0, "p": 0, "q": 0,
    "r": 0, "s": 0, "t": 0, "u": 0, "v": 0, "w": 0, "x": 0, "y": 0, "z": 0}

with open ("data.txt", "r") as f:
    for line in f:
        for word in line.split():
            for i in count:
                if word[:1] == i.lower():
                    count[i] = count[i] + 1

for i in count:
    print i + ": " + json.dumps(count[i])

<filename>count-letter.py
#!/usr/bin/python
import json

count = {"a": 0, "b": 0, "c": 0, "d": 0, "e": 0, "f": 0, "g": 0, "h": 0,
    "i": 0, "j": 0, "k": 0, "l": 0, "m": 0, "n": 0, "o": 0, "p": 0, "q": 0,
    "r": 0, "s": 0, "t": 0, "u": 0, "v": 0, "w": 0, "x": 0, "y": 0, "z": 0}

with open ("data.txt", "r") as f:
    for line in f:
        for word in line.split():
            for i in count:
                if word[:1] == i.lower():
                    count[i] = count[i] + 1

for i in count:
    print i + ": " + json.dumps(count[i])

#!/usr/bin/python