ValueError: The 'loc' parameter must be a string or an integer between 0 and 10, but you provided 'center left' which is a valid string but misspelled.
ID: python/matplotlib-legend-loc-error
Version Compatibility
| Version | Status | Introduced | Deprecated | Notes |
|---|---|---|---|---|
| 3.8 | active | — | — | — |
| 3.9 | active | — | — | — |
Root Cause
The 'loc' string for legend placement is case-sensitive and must be one of the predefined strings like 'upper left', 'lower right', etc.; 'center left' is not valid (should be 'center left'? actually 'center left' is valid? Wait, this error is about misspelling: 'center left' vs 'center left'? Actually 'center left' is valid, but if user typed 'centre left' or 'center left' with extra space, it fails. Let's correct: The error occurs when user provides a string that is not in the allowed list, e.g., 'center left' is valid, but if misspelled as 'centr left', it raises ValueError.
generic中文
图例位置的'loc'字符串区分大小写，必须是预定义字符串之一，例如'upper left'、'lower right'等；拼写错误（如'centr left'）会导致此错误。
Workarounds
-
95% success Use the exact valid string from documentation
plt.legend(loc='upper left') # or 'lower right', 'center', etc.
-
90% success Use a valid numeric code (0-10) for backward compatibility
plt.legend(loc=2) # 2 corresponds to 'upper left'
Dead Ends
Common approaches that don't work:
-
Using a numeric code like 10 thinking it maps to 'center'
70% fail
Numeric codes are deprecated in newer versions and may not work as expected; also 'center left' is not a single numeric code.
-
Ignoring case sensitivity and trying 'Upper Left'
80% fail
The strings are case-sensitive; 'Upper Left' is not valid, only 'upper left' works.