added string-1 problems

Author: saurabhmithe

Solutions/string-1/extra_end.py

@@ -0,0 +1,10 @@
+# Given a string, return a new string made of 3 copies of the last 2
+# chars of the original string. The string length will be at least 2.
+
+# extra_end('Hello') → 'lololo'
+# extra_end('ab') → 'ababab'
+# extra_end('Hi') → 'HiHiHi'
+
+
+def extra_end(str):
+    return str[-2:] * 3

Solutions/string-1/first_two.py

@@ -0,0 +1,14 @@
+# Given a string, return the string made of its first two chars,
+# so the String "Hello" yields "He". If the string is shorter
+# than length 2, return whatever there is, so "X" yields "X",
+# and the empty string "" yields the empty string "".
+
+# first_two('Hello') → 'He'
+# first_two('abcdefg') → 'ab'
+# first_two('ab') → 'ab'
+
+
+def first_two(str):
+    if len(str) > 2:
+        return str[0:2]
+    return str

Solutions/string-1/make_out_word.py

@@ -0,0 +1,10 @@
+# Given an "out" string length 4, such as "<<>>", and a word, return a new
+# string where the word is in the middle of the out string, e.g. "<<word>>".
+
+# make_out_word('<<>>', 'Yay') → '<<Yay>>'
+# make_out_word('<<>>', 'WooHoo') → '<<WooHoo>>'
+# make_out_word('[[]]', 'word') → '[[word]]'
+
+
+def make_out_word(out, word):
+    return out[:2] + word + out[-2:]