﻿ Python: Get all possible two digit letter combinations from a digit string - w3resource # Python: Get all possible two digit letter combinations from a digit string

## Python Basic - 1: Exercise-13 with Solution

Write a Python program to get all possible two digit letter combinations from a digit (1 to 9) string.

string_maps = {
"1": "abc",
"2": "def",
"3": "ghi",
"4": "jkl",
"5": "mno",
"6": "pqrs",
"7": "tuv",
"8": "wxy",
"9": "z"
}

Pictorial Presentation: Sample Solution:

Python Code:

``````def letter_combinations(digits):
if digits == "":
return []
string_maps = {
"1": "abc",
"2": "def",
"3": "ghi",
"4": "jkl",
"5": "mno",
"6": "pqrs",
"7": "tuv",
"8": "wxy",
"9": "z"
}
result = [""]
for num in digits:
temp = []
for an in result:
for char in string_maps[num]:
temp.append(an + char)
result = temp
return result

digit_string = "47"
print(letter_combinations(digit_string))
digit_string = "29"
print(letter_combinations(digit_string))
``````

Sample Output:

```['jt', 'ju', 'jv', 'kt', 'ku', 'kv', 'lt', 'lu', 'lv']
['dz', 'ez', 'fz']
```

Flowchart: ## Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Python Code Editor :

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

﻿

## Python: Tips of the Day

Iterating over dictionaries using 'for' loops:

I am a bit puzzled by the following code: d = {'x': 1, 'y': 2, 'z': 3} for key in d: print key, 'corresponds to', d[key] What I don't understand is the key portion. How does Python recognize ...

key is just a variable name.

```for key in d:
```

For Python 3.x:

```for key, value in d.items():
```

For Python 2.x:

```for key, value in d.iteritems():
```

To test for yourself, change the word key to poop.

In Python 3.x, iteritems() was replaced with simply items(), which returns a set-like view backed by the dict, like iteritems() but even better. This is also available in 2.7 as viewitems().

The operation items() will work for both 2 and 3, but in 2 it will return a list of the dictionary's (key, value) pairs, which will not reflect changes to the dict that happen after the items() call. If you want the 2.x behavior in 3.x, you can call list(d.items()).

Ref: https://bit.ly/37dm0Qo