Member Avatar for k_en

Do anyone know why i got this error ? Do i have to import anything in order to use string.lower() & string.upper() ?

sentence = "how are you"
newS = string.lower(sentence)
NameError: name 'string' is not defined
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Short expert note: the first error happened because there was no name called string in scope. Case-conversion is implemented as methods on the string type (the str object), so calling the method on the value is the normal approach; the string module in modern Python mainly exposes constants and Template, not free lower/upper functions. This is why older examples that import string differ from current idioms. (docs.python.org)

The second error — AttributeError: 'tuple' object has no attribute 'lower' — means the variable being used is a tuple, and tuples do not provide string methods. Common causes: a stray comma when assigning a literal (which makes a single-element tuple), a function that returned multiple values, or unpacking that produced a tuple. Quick, safe checks and a small fix:

# quick checks
print(type(val), repr(val))

# trailing-comma pitfall:
val = "hello",    # val is a tuple ('hello',)

# if val is a tuple of strings, join them into one string first
if isinstance(val, tuple):
    text = " ".join(val)   # join requires all items to be str
else:
    text = str(val)

print(text.lower())

Use isinstance() to test types and str.join() to turn a sequence of strings into one string before calling string methods. (docs.python.org)

Extra tips: prefer casefold() for aggressive caseless comparisons, avoid importing the string module just to change case (that was a Python‑2 era pattern), and check for accidental commas or name shadowing (a local variable named string hides an import). If the code comes from old Python 2 examples, expect some legacy differences in the string module compared with Python 3. (docs.python.org)

Acknowledgement: ’s report of the two errors and ’s diagnosis (method vs module, and the tuple possibility) are consistent with the above debugging steps.

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Member Avatar for vegaseat

There are two ways to do this ...

# older way, needs to import string module
import string

sentence = "HOW ARE YOU"
newS = string.lower(sentence)
print newS

# newer way, no import needed
newerS = sentence.lower()
print newerS
Member Avatar for k_en

Why i got this error ?

newS = sentence.lower()
AttributeError: 'tuple' object has no attribute 'lower'
Member Avatar for vegaseat

The only way I can recreate this error is to make variable sentence a tuple ...

#sentence = "HOW ARE YOU"
sentence = 'HOW', 'ARE', 'YOU'
newS = sentence.lower()
print newS

Are you using an older version of Python?

Member Avatar for k_en

Thank You.

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